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# Minimum number of swaps required to sort an array of first N number

• Difficulty Level : Medium
• Last Updated : 20 Apr, 2021

Given an array arr[] of distinct integers from 1 to N. The task is to find the minimum number of swaps required to sort the array.
Example:

```Input: arr[] = { 7, 1, 3, 2, 4, 5, 6 }
Output: 5
Explanation:
i           arr             swap (indices)
0   [7, 1, 3, 2, 4, 5, 6]   swap (0, 3)
1   [2, 1, 3, 7, 4, 5, 6]   swap (0, 1)
2   [1, 2, 3, 7, 4, 5, 6]   swap (3, 4)
3   [1, 2, 3, 4, 7, 5, 6]   swap (4, 5)
4   [1, 2, 3, 4, 5, 7, 6]   swap (5, 6)
5   [1, 2, 3, 4, 5, 6, 7]
Therefore, total number of swaps = 5

Input: arr[] = { 2, 3, 4, 1, 5 }
Output: 3```

Approach:

• For each index in arr[].
• Check if the current element is in it’s right position or not. Since the array contains distinct elements from 1 to N, we can simply compare the element with it’s index in array to check if it is at its right position.
• If current element is not at it’s right position then swap the element with the element which has occupied its place.
• Else check for next index.

Below is the implementation of the above approach:

## C++

 `#include ``using` `namespace` `std;` `// Function to find minimum swaps``int` `minimumSwaps(``int` `arr[],``int` `n)``{``    ``// Initialise count variable``    ``int` `count = 0;``    ``int` `i = 0;``    ` `    ``while` `(i < n)``    ``{` `        ``// If current element is``        ``// not at the right position``        ``if` `(arr[i] != i + 1)``        ``{` `            ``while` `(arr[i] != i + 1)``            ``{``                ``int` `temp = 0;` `                ``// Swap current element``                ``// with correct position``                ``// of that element``                ``temp = arr[arr[i] - 1];``                ``arr[arr[i] - 1] = arr[i];``                ``arr[i] = temp;``                ``count++;``            ``}``        ``}` `        ``// Increment for next index``        ``// when current element is at``        ``// correct position``        ``i++;``    ``}``    ``return` `count;``}` `// Driver code``int` `main()``{``    ``int` `arr[] = { 2, 3, 4, 1, 5 };` `    ``int` `n = ``sizeof``(arr)/``sizeof``(arr);``    ` `    ``// Function to find minimum swaps``    ``cout << minimumSwaps(arr,n) ;``}` `// This code is contributed by AnkitRai01`

## Java

 `// Java program to find the minimum``// number of swaps required to sort``// the given array``import` `java.io.*;``import` `java.util.*;` `class` `GfG {` `    ``// Function to find minimum swaps``    ``static` `int` `minimumSwaps(``int``[] arr)``    ``{``        ``// Initialise count variable``        ``int` `count = ``0``;``        ``int` `i = ``0``;``        ``while` `(i < arr.length) {` `            ``// If current element is``            ``// not at the right position``            ``if` `(arr[i] != i + ``1``) {` `                ``while` `(arr[i] != i + ``1``) {``                    ``int` `temp = ``0``;` `                    ``// Swap current element``                    ``// with correct position``                    ``// of that element``                    ``temp = arr[arr[i] - ``1``];``                    ``arr[arr[i] - ``1``] = arr[i];``                    ``arr[i] = temp;``                    ``count++;``                ``}``            ``}` `            ``// Increment for next index``            ``// when current element is at``            ``// correct position``            ``i++;``        ``}``        ``return` `count;``    ``}` `    ``// Driver code``    ``public` `static` `void` `main(String[] args)``    ``{``        ``int` `arr[] = { ``2``, ``3``, ``4``, ``1``, ``5` `};` `        ``// Function to find minimum swaps``        ``System.out.println(minimumSwaps(arr));``    ``}``}`

## Python3

 `# Python3 program to find the minimum``# number of swaps required to sort``# the given array` `# Function to find minimum swaps``def` `minimumSwaps(arr):``    ` `    ``# Initialise count variable``    ``count ``=` `0``;``    ``i ``=` `0``;``    ``while` `(i < ``len``(arr)):` `        ``# If current element is``        ``# not at the right position``        ``if` `(arr[i] !``=` `i ``+` `1``):` `            ``while` `(arr[i] !``=` `i ``+` `1``):``                ``temp ``=` `0``;` `                ``# Swap current element``                ``# with correct position``                ``# of that element``                ``temp ``=` `arr[arr[i] ``-` `1``];``                ``arr[arr[i] ``-` `1``] ``=` `arr[i];``                ``arr[i] ``=` `temp;``                ``count ``+``=` `1``;``            ` `        ``# Increment for next index``        ``# when current element is at``        ``# correct position``        ``i ``+``=` `1``;``    ` `    ``return` `count;` `# Driver code``if` `__name__ ``=``=` `'__main__'``:``    ``arr ``=` `[ ``2``, ``3``, ``4``, ``1``, ``5` `];` `    ``# Function to find minimum swaps``    ``print``(minimumSwaps(arr));``    ` `# This code is contributed by 29AjayKumar`

## C#

 `// C# program to find the minimum``// number of swaps required to sort``// the given array``using` `System;` `class` `GfG``{` `    ``// Function to find minimum swaps``    ``static` `int` `minimumSwaps(``int``[] arr)``    ``{``        ``// Initialise count variable``        ``int` `count = 0;``        ``int` `i = 0;``        ``while` `(i < arr.Length)``        ``{` `            ``// If current element is``            ``// not at the right position``            ``if` `(arr[i] != i + 1)``            ``{` `                ``while` `(arr[i] != i + 1)``                ``{``                    ``int` `temp = 0;` `                    ``// Swap current element``                    ``// with correct position``                    ``// of that element``                    ``temp = arr[arr[i] - 1];``                    ``arr[arr[i] - 1] = arr[i];``                    ``arr[i] = temp;``                    ``count++;``                ``}``            ``}` `            ``// Increment for next index``            ``// when current element is at``            ``// correct position``            ``i++;``        ``}``        ``return` `count;``    ``}` `    ``// Driver code``    ``public` `static` `void` `Main(String[] args)``    ``{``        ``int` `[]arr = { 2, 3, 4, 1, 5 };` `        ``// Function to find minimum swaps``        ``Console.WriteLine(minimumSwaps(arr));``    ``}``}` `// This code is contributed by 29AjayKumar`

## Javascript

 ``
Output:

`3`

Time Complexity: O(N) where N is the size of array.
Auxiliary Space: O(1)

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