Minimum number of swaps to sort an array in descending order. For example, Let the array be [3, 4,2 .
Minimum number of swaps to sort an array in descending order Oct 3, 2025 · Given an array arr [] of size N, the task is to find the minimum moves to the beginning or end of the array required to make the array sorted in non-decreasing order. Examples: Input: arr [] = {8, 4, 5, 3, 2, 7} Output: 57 Explanation: Swap element at index 4 with index 5 - cost (arr [4]*arr [5]) = (2*7) = 14, Array becomes {8, 4, 5, 3, 7, 2} then, swap element at index 0 with 5 - cost (arr [0]*arr Jul 23, 2025 · Explanation: arr is sorted in increasing order Input: arr = {3,2,5,4,1} Output: 5 4 3 2 1 Explanation: arr is sorted in decreasing order Sort an Array using Library Function C++ STL provides std::sort () method which is used to sort the array in any desired order. Each interchange incurs a cost, which is calculated as the sum of the two values involved in the interchange. g. Input: nums = {2,4,5,1,3} Output: 3 Jul 23, 2025 · Find the minimum number of swaps required to sort the array given array in descending order using the approach discussed in this article. So, we'd have as input an unordered array of integers. An array contains four occurrences of 0, five occurrences of 1, and three occurrences of 2 in any order. # The number of swaps required to sort the elements in descending order is 1. We can perform a swap operation on any two adjacent elements in the array. Find the 'enclosed subgraphs'. Insertion Sort: Insertion sort similarly to the way we sort playing cards in our hands. This minimizes the number of exchanges and is a key metric in sorting algorithms, as reducing swaps often improves efficiency and performance when organizing data structures. i. When we subtract 1 from this number we can get the number of swaps. You will also see how to sort an array in C# in descending order using the Reverse method. In one operation, we can replace nums[1] with 2 and 4 and convert nums to [5,2,4,7]. Below is the implementation of the above approach: An efficient algorithm to find the minimum number of swaps required to sort the array in ascending order. First we find the smallest element and swap it with the first element. Count = 1. For instance, given an input array [3, 2, 1], the desired output would be 2 swaps to sort the array in ascending order. The sort is carried out by interchanging the position of two values one at a time until the sequence is in the proper order. swapping 4 and 1 then 4 and 3). In fact, your approach is just a special case of the approach at the question you link to. So, I suggest that you will find a better algorithm by doing the following: 1) First, sort the array into descending order using the built in sorting function of C#. The minimum swaps problem asks: Given an array of distinct elements, what is the minimum number of swaps required to sort the array in ascending order? A swap operation exchanges two elements in the array. Examples: Input : arr [] = {5, 3, 10, 1} Output : arr [] = {10, 5, 3, 1} Input : arr [] = {1, 50, 100, 25} Output : arr [] = {100, 50, 25, 1} Prerequisite: Heap sort using min heap. Selection Sort: In selection sort, the input array is divided into two parts: a sorted part and an unsorted part. The algorithm repeatedly finds the minimum element in the unsorted part and swaps it with the leftmost element of the The problem with bubble sort is its worst case scenario. Sample Test Cases: Input 1: Oct 24, 2018 · You need to find the minimum number of swaps required to sort the array in ascending order. It can be used to sort an array of elements in either ascending or descending order, depending on whether a min-heap or a max-heap is used. In Given an array with distinct elements, what is the minimum number of swap needed to sort it? For example, the array [4, 2, 1, 3] needs at least 2 swaps (e. An array is called beautiful if all the elements of the array are in either ascending or descending order. * For example, consider nums = [5,6,7]. e from the highest element of the list to the lowest using python. Step 4: arr [3] shifts 2 places Sep 29, 2022 · Given an array arr [] of non negative integers. For the given array find the sequence of swaps that makes the array sorted in the non-descending order. Aug 8, 2024 · This article revolves around the minimum number of swaps to sort an array. in minimum number of swaps where only adjacent students can be s Apr 30, 2024 · Embark on a journey through the world of array manipulation with this comprehensive guide from GeeksforGeeks on finding the minimum number of swaps required to sort an array. Find the minimum number of swaps needed to sort the array in ascending order. What is the minimum number of swaps needed to sort such an array in the worst case? Give an ordering of elements in the above array so that the minimum number of swaps needed to sort the array When the smallest element is in the last position, then it takes more time to sort in ascending order, but takes less time to sort in descending order. So, if the input is like nums = [2, 5, 6, 3, 4], then the output will be 2 because initially nums has [2, 5, 6, 3, 4]. Find the minimum number of swaps required to sort the array in ascending and descending order. 2. You must solve the problem without using any built-in functions in O (nlog (n)) time complexity and with the smallest space complexity possible. Aug 4, 2017 · I can handle large numbers with this code as well but I need to improve my execution time. Jul 27, 2025 · Selection Sort: Selection sort is another sorting technique in which we find the minimum element in every iteration and place it in the array beginning from the first index. My solution/issue: Sep 1, 2016 · You just have to count the number of necessary swaps in bubble sort. N, which means we don't actually have to do swaps just count them. I need to find minimum number of swaps required to sort an array in descending order. Heapsort is not a stable sort, meaning it does not preserve the relative order of equal elements. Feb 12, 2019 · 2 You are given an unordered array consisting of consecutive integers [1, 2, 3, , n] without any duplicates. Each iteration of selection sort consists of scanning across the array, finding the minimum element that hasn't already been placed yet, then swapping it to the appropriate position. Using Min Heap Implementation - O (n Log n) Time Build a min heap from the input data. Given an array of integers (duplicates are possible), find the minimum number of swaps to sort the array. Dec 23, 2019 · Problem statement Given an array of N distinct elements, find the minimum number of swaps required to sort the array Dec 12, 2023 · Minimum number of swaps required to sort an array - GeeksforGeeks A Computer Science portal for geeks. Jul 23, 2025 · The selection sort algorithm sorts an array by repeatedly finding the minimum element (considering ascending order) from unsorted part and putting it at the beginning. Swaps can exchange any pair of elements (they need not be adjacent). We can use that the we know what the sort result would be: 1. I was able to get a solution with selection sort but it has a time complexity of O (n^2) but i need an efficient solution. In every iteration of selection sort, the minimum element (considering ascending order) from the C# sort array or sort C# array. That question doesn't actually use a graph Aug 16, 2021 · Given an array arr [] of distinct integers from 1 to N. May 22, 2019 · I am trying to sort list in decreasing order and get the number of swaps required to sort the list in decreasing order [3, 1, 2] → [3, 2, 1]. org/minimum-number-swaps-required-sort-array/ I will repeat it below: Given an array of n distinct elements, find the minimum number of swaps required to sort the array. 2) Now, you can use this sorted array as a 0 A swap is not equivalent to a comparison. Aug 29, 2023 · Sorting an array using a minimum number of swaps? We will learn about minimum swaps to sort array in descending order or with duplicates. You are allowed to swap any two elements. Here is my code that got accepted. Minimum Swaps to Sort https://www. Example: Input: arr[] = { 7, 1, 3 Can you solve this real interview question? Minimum Replacements to Sort the Array - You are given a 0-indexed integer array nums. In this article, we will learn different ways to sort an array in descending order in C. Jun 7, 2017 · L2 = [2,5,4,3] The minimal number of swaps is one (swap 5 and 3 in L2 to get L1), but number of inversions is three: (5 4), (5 3), and (4 3) pairs are in the wrong order. It should be fast enough to detect number of swaps in array Jul 11, 2025 · Using std::sort () Function C++ STL provides the std::sort () algorithm to sort the given range of elements. Examples: Input: arr [] = {4, 7, 2, 3, 9} Output: 2 Explanation: Perform the following operations: Step 1: Move the element 3 to the start of the array. (the elements can be in {1,2,3}) Write shortest code that detect how many swaps (minimum) are needed to sort (in increasing order) any array of unique positive integers. The move-to-front operation is to pick any item and place it in first position. The code what i have got ,timed out for a few test cases. For example, given the array arr = [7, 1, 3, 2, 4, 5, 6] we perform the following steps: Jul 9, 2020 · The problem statement We are given an array of distinct integers which are not sorted. Mar 15, 2023 · Given an array arr [], the task is to find the minimum operations required to sort the array in increasing order. It will focus on various swaps required and the algorithmic approach to use them in C++ programming language. We find the number of elements dissimilar to the sorted array. Step 3: arr [2] stays in its initial position. Sample Input 2 7 1 3 5 2 4 6 7 Sample Output 2 3 Explanation 2 Given array After swapping we get After swapping we get After In this problem your goal is to sort an array consisting of n integers in at most n swaps. Apr 29, 2025 · Given a binary array, the task is to find the minimum number of swaps needed to sort this binary array. Let the count be S2. If two numbers have the same digit sum, the smaller number appears first in the sorted order. Nov 25, 2015 · 4 The number of inversions of a permutation relative to another permutation is the minimum number of adjacent swaps required to transform one into the other. In this article and code examples, you will learn how to sort an array in C# in ascending order. The cost of swapping two elements X and Y is X*Y. The task is to count a number of move-to-front operations to arrange items as {1, 2, 3, n}. Suppose, we have an array called nums and we have to find the number of swaps needed to make nums sorted in any order, either ascending or descending. Dec 27, 2019 · Is there an efficient algorithm to find the minimum number of swaps needed to put this array into sorted order? Note: I'm not actually trying to sort the array, rather to find out the minimum number of swaps that make it in ascending order. I need to write a sorting routine that sorts an array of length 5 using 7 comparisons in the worst case (I've proven that 7 will be needed, because of the heig You need to sort the array in increasing order based on the sum of the digits of each number. So, I hope you can see it's not impossible to do the minimal number of swaps to get to sorted order, but it's not worth it, because it requires a ridiculous number of comparisons. Jul 23, 2025 · Insertion sort and selection sort are two popular sorting algorithms, and their main difference lies in how they select and place elements in a sorted sequence. By default, it sorts the array in ascending order, but we can change it to descending order using custom comparator function. The only way to sort a primitive array in descending order is, first sort the array in ascending order and then reverse the array in place. The algorithm repeatedly finds the minimum (or maximum, depending on the sorting order) element from the unsorted part and swaps it with the first element of the unsorted part. Jul 23, 2025 · Given an array A [] of size N (1 ≤ N ≤ 105), the task is to calculate the number of swaps required to sort the array using insertion sort algorithm. The process continues until no more swaps are needed, indicating that the list is sorted. Can you solve this real interview question? Minimum Swaps To Make Sequences Increasing - You are given two integer arrays of the same length nums1 and nums2. Using an optimized Bubble Sort algorithm with early exit detection, the program efficiently counts swaps and sorts the array in the order that requires fewer swaps. The formula I came up with is given an unsorted array and it's descending or ascending order. Jul 23, 2025 · Selection Sort is a comparison-based sorting algorithm. Sorting a C# array is a common operation for programmers. Finding the minimum number of swaps required to put a permutation of 1. How Bubble Sort works? We use Bubble Sort algorithm to sort the elements in either ascending or descending order. The algorithm maintains two subarrays in a given array. The simplest way to count number of inversions follows from the definition: A pair of elements (p i,p j) is called an inversion in a permutation p if i < j and p i > p j. If you want to minimize the number of swaps, though Jul 29, 2020 · 2 I have an array of size n, which contain elements from 1 to n, in random order. In one operation you can replace any element of the array with any two elements that sum to it. Start: 1, 2, 5 Dec 4, 2019 · What is a Sorting Algorithm? Sorting algorithms are a set of instructions that take an array or list as an input and arrange the items into a particular order. # The best way is to sort in descending order and swaps required is 1. Dec 22, 2019 · I'm doing a fairly easy HackerRank test which asks the user to write a function which returns the minimum number of swaps needed to sort an unordered vector in ascending order, e. The subarray which is already sorted. Remaining subarray which is unsorted. Oct 11, 2025 · 4 Sum - Closest Quadruple Surpasser Counts in an Array Minimum consecutive number subsets Min swaps to reach given array Making Array Elements Same Sort after applying an equation Closest Pair of Points Quick Links : ‘Practice Problems’ on Sorting Top Sorting Interview Questions ‘Quizzes’ on Sorting Learn Data Structure and Algorithms Optimal-Array-Sorting- This repository contains a C program that determines whether an array should be sorted in ascending or descending order based on the minimum number of swaps required. Contribute to manishanit/Leetcode_solutions development by creating an account on GitHub. Swap items in the list to get to the correct order, but only swap items within the same subgraph. * For example, if nums1 = [1,2,3,8], and nums2 = [5,6,7,4], you can swap the element at i = 3 to obtain nums1 = [1,2,3,4] and nums2 = [5,6,7,8]. For [3,9,2,4,2] it should be 2 : [3, 9, 2, 4, 2] -> [2, 9, 3 Given an array of n distinct elements. Sorts are most commonly in numerical or a form of alphabetical (called lexicographical) order, and can be in ascending Sep 12, 2024 · To solve this problem, we need to determine the minimum number of swaps required to sort the array in either ascending or descending order using Bubble Sort. In one operation, you are allowed to swap nums1[i] with nums2[i]. A swap means replacing element at index i in A with the corresponding B element and vice versa. Swaps are performed consecutively, one after another. Jul 17, 2023 · Question In this question, we’re given an unsorted array of consecutive integers. split()) for i,x in enumerate(l): if x-(i+1) > 2: print "Too chaotic" break else: counter = 0 while 1: flag = True for i in range(len(l)-1): if l[i] > l[i+1]: l[i],l[i+1] = l[i+1],l[i] counter += 1 flag = False if flag Aug 9, 2015 · 2 I have been given an array and I'm asked to find out the number of Swaps required to sort the array using Bubble Sort Now we know that, we can find the comparisons by n(n-1)/2 but what I need is the number of actual swaps My first instinct was to use bubble sort and with each swap (), I incremented a Swap variable. We compare two adjacent elements and swap them only if they are not in the correct position. Points to remember Bubble Sort requires (n – 1) pass to sort an array arr having n Feb 22, 2025 · Given an array of elements, sort the array in decreasing order using min heap. Jul 7, 2020 · So, we need a minimum of swaps to sort the array in ascending order. It can vary between different sorting algorithms. We are allowed to swap any of the two items of the array to eventually make it sorted in ascending order. This is true even if the array can contain duplicates. When the smallest element is in the last position, then it takes more time to sort in ascending order, but takes less time to sort in descending order. 1 Answers I would start with a copy of the array in descending order for getting the right index of the items. Sep 28, 2023 · The minimum number of swaps required to sort an array depends on the specific elements and their initial arrangement. Thus, swaps occur any time a neighboring pair is "out of order. Step 2: arr [1] shifts 1 place to the left. Return the minimum number of swaps required to rearrange nums into this sorted order. Mar 9, 2024 · Problem Formulation: The task at hand involves determining the minimum number of swap operations required to sort a given sequence of numbers into ascending order in Python. So we know that selection sort gives the minimum number of swaps to sort an array. For instance, given the input sequence [3, 2, 1], the desired output is 2 swaps to sort the sequence into [1, 2, 3]. " In the worst case, every comparison would result in a swap when one has an array in descending order. Jan 29, 2018 · The question is from here: https://www. In this illuminating article, you'll explore essential concepts and algorithms for optimizing the arrangement of elements within an array, a critical skill for enhancing the efficiency of sorting algorithms. Example 1: Input: nums = [5,2,3,1] Output: [1,2,3,5] Explanation: After sorting the array, the positions of Jan 8, 2014 · Lemma 3: We need to perform at least NI swaps of adjacent elements in order to sort the array where NI is the number of inversions in the array Proof: In a sorted array there are no inversions. An algorithm to find the minimum number of swaps required to sort the array in ascending order. The task is to find the minimum number of swaps required to sort the array. May 4, 2020 · Your approach is correct. At this point, the smallest item is stored at Dec 20, 2009 · I need some help with my CS homework. I'm not worried about the stability. T = input() for test in range(T): n = input() l = map(int, raw_input(). The array is to be sorted using swap operations (elements that are swapped need to be adjacent). Considering I can swap any two elements any number of times, how can I find minimum numbers of such swap to make array sorted? 1 Answers I would start with a copy of the array in descending order for getting the right index of the items. An array is called Bubble Sort is the simplest sorting algorithm that works by repeatedly swapping the adjacent elements if they are in the wrong order. For example, Let the array be [3, 4,2 Can you solve this real interview question? Sort an Array - Given an array of integers nums, sort the array in ascending order and return it. Examples : Input : arr [] = {3, 2, 1} Output : 3 We need to do following swaps (3, 2), (3, 1) and (1, 2) Input : arr [] = {1, 20, 6, 4, 5} Output : 5 Recommended Problem Minimum number of swaps Jan 18, 2020 · Sorting algorithms are a set of instructions that take an array or list as an input and arrange the items into a particular order. In insertion sort, the number of comparisons is the same as for bubble sort. As Wikipedia explains: One thing which distinguishes selection sort from other sorting algorithms is that it makes the minimum possible number of swaps, n − 1 in the worst case. Find the minimum number of swaps required to sort the array in strictly increasing order. Oct 11, 2021 · Is there an efficient way to calculate the optimal swaps required to sort an array? The element of the array can be duplicated, and there is a given upper limit=3. $ [5,3,1,7,2,6,4]$ Pick ONE option 4,5 5,4 4,4 5,5 Clear Selection Saved! Sep 16, 2012 · Thanks! A “costed sort” is an algorithm in which a sequence of values must be arranged in ascending order. Jul 23, 2025 · Sort an array in descending order means arranging the elements in such a way that the largest element at first place, second largest at second place and so on. Problem:We have an unordered array consisting of distinct int Jun 13, 2013 · The problem with your algorithm is that it only attempts swapping adjacent elements. This process continues until the entire array is sorted. Example 1: Jan 23, 2024 · Introduction S election Sort is a simple comparison-based sorting algorithm that works by dividing the input list into two parts: the sorted part and the unsorted par t. Nov 17, 2023 · Understanding Bubble Sort Bubble Sort is a straightforward sorting algorithm that works by repeatedly stepping through the list to be sorted, comparing each pair of adjacent items and swapping them if they are in the wrong order. The easiest way to sort an array in C is by using qsort () function. In a naive implementation of selection sort, this means that there will always be n - 1 swaps made regardless of distribution of elements in the input array. A little bit of abstract algebra shows that we're interested in finding the rotation of the input array that minimizes the number of inversions relative to sorted order. Our task is to write a piece of an algorithm that works out the minimum number of swaps that are required to sort the array as expected. This process is repeated until the entire list Jul 15, 2025 · Given an array of N distinct positive integers. # Time Limit (secs) # 1 # Examples # Example 1: # Input: # 5 # 4 5 3 2 1 # Output: # 1 # Explanation: # The number of swaps required to sort the elements in ascending order is 9. Just use heapsort. This function uses a combination of quicksort, insertion sort and heapsort algorithm. Examples: Input: A [] = {2, 1, 3, 1, 2} Output: 4 Explanation: Step 1: arr [0] stays in its initial position. 3,4,2,5,1 is best sorted by swapping 3 with 5, which is an unadjacent swap, and then 2 with 3. org/problems/minimum-swaps/1 Given an array of n distinct elements. We are allowed to swap only adjacent elements. Is there any way that we can optimise the Nov 18, 2021 · Problem Statement Given an array with distinct integers, find the minimum number of swaps required to sort it. geeksforgeeks. May 23, 2019 · What should be the better approach to find the minimum number of swaps required to sort the array in ascending order? Mar 19, 2018 · Given two arrays of equal length A = [1,8,12,11], B = [7,3,10,15], sort them in ascending order by only performing swaps. Syntax std::sort(first, last, comp); where, first and last are the iterator to the beginning and the end of the Thus, we need to identify all such cycles"," and add their length-1 values to find the minimum swaps"," we do not sort the array to find this number","*/","","#include <iostream>","using namespace std;","","long long count_min_swaps(long long *arr, long long n);","","int main(){"," // read the data"," long long n, i; cin >> n;"," long long a[n Jul 23, 2025 · Given an array of size n such that array elements are in range from 1 to n. Return the minimum number 0 The problem: You are given an unordered array consisting of consecutive integers [1, 2, 3, , n] without any duplicates. It contains well written, well thought and well explained computer science and… You are given an unordered array consisting of consecutive integers [1, 2, 3, , n] without any duplicates. After completing the above steps, print the minimum of the value S1 and S2 as the resultant minimum number of swaps required. Jul 23, 2025 · This approach uses cycle detection method to find out the minimum number of swaps required to sort the array. Jul 17, 2024 · The minimum number of swaps to sort an array is the smallest quantity of element swaps needed to arrange the array in ascending or descending order. def no_swap(a): sorted_a=sorted(a) rev_a=list(reversed(a)) b=a[:] n=len(a) noswap1=0 noswap2= Jul 12, 2025 · Sorting an array in ascending order means arranging the elements in the order from smallest element to largest element. This is also true for two-dimensional primitive arrays. The task is to find the minimum cost to sort the given array. Examples: Input Jul 25, 2025 · Learn how to sort integer arrays in descending order in Java without built-in methods by writing your own comparison logic and loop-based sorting code. Solutions for problems of leetcode. Nov 8, 2009 · That will work fine with 'Array of Objects' such as Integer array but will not work with a primitive array such as int array. . It sorts an array by repeatedly selecting the smallest (or largest) element from the unsorted portion and swapping it with the first unsorted element. We can also sort the array using this function. Thus, a selection sort also gets divided into a sorted and unsorted subarray. Jul 23, 2025 · The selection sort algorithm sorts an array by repeatedly finding the minimum element (considering ascending order) from the unsorted part and putting it at the beginning. The number of swaps depends on the actual order of the elements. Here’s a step-by-step approach: Jul 23, 2025 · Given an array arr [] consisting of N integers, the task is to find the minimum cost to sort the given array arr [] in ascending order by swapping any pair of elements (X, Y) such that the cost of swapping is (X + Y). Return the minimum number of operations to You are given an unordered array consisting of consecutive integers [1, 2, 3, , n] without any duplicates. If an element is not in its correct position, it indicates that it is a part of a cycle with one or more other elements that also need to be moved. Sorts are most commonly in numerical or a form of alphabetical (or lexicographical) order, Mar 3, 2024 · Problem Formulation: Calculating the number of swaps required to sort an array is a common algorithmic challenge that involves transforming an unsorted array into a sorted one using the minimal number of swap operations. For that list, in any order the elements would be, there would be 15 comparisons. In one operation, you can set each occurrence of one element to 0. We need to find out the minimum number of swaps — the process of interchanging the position of two values in the array — required to sort the array in ascending order. Mar 5, 2017 · 2 Given an array, I need to sort the array (if not already sorted) in either decreasing or increasing order so that number of swaps are minimized. Examples: Input: arr [] = {3, 2, 1} Output: 4 Explanation: Following are the swapping of array elements performed to sort the array: Swapping the array elements at index 0 and 2 Given array After swapping we get After swapping we get After swapping we get So, we need a minimum of swaps to sort the array in ascending order. Find the minimum number of swaps required to sort the array in ascending order Eg Input: nums = {2, 8, 5, 4} Output: 1 Explaination: swap 8 with 4. The Swap Sort Algorithm, also known as the Bubble Sort Algorithm, is a simple and intuitive sorting algorithm used to arrange a list of elements in a specific order, either ascending or descending. N in order. In this tutorial, we will learn about Bubble Sort which is one of the easiest sorting algorithms. Apr 5, 2019 · I had an algorithm to solve the problem where professor has to sort the students by their class score like 1 for good and 0 for bad. You need to find the minimum number of swaps required to sort the array in ascending order. pws flrm lnrh wks bea xjg ifhv afwxn bogh speno tptr ryqoud uvia vzfan nfwgso