Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Largest permutation after at most k swaps in C++
In this tutorial, we are going to write a program that finds the largest permutation after at most k swaps.
Let's see the steps to solve the problem.
- Initialise the array.
- Initialise an array to store the index with size n + 1.
- Iterate over the array and store the index of each element in the position array.
- Write a loop that iterate till n and k is greater than 0.
- Store the position of n - i element in a temp variable.
- Update position of current element arr[i] with position[n - i].
- Update the position position[n - i] with current index i.
- Swap the current element arr[i] with arr[temp. Decrement k.
- Print the array elements.
Example
Let's see the code.
#include <bits/stdc++.h>
using namespace std;
void getLargestPermutation(int arr[], int n, int k) {
int position[n + 1];
for (int i = 0; i < n; ++i) {
position[arr[i]] = i;
}
for (int i = 0; i < n && k; ++i) {
if (arr[i] == n - i) {
continue;
}
int temp = position[n - i];
position[arr[i]] = position[n - i];
position[n - i] = i;
swap(arr[temp], arr[i]);
--k;
}
}
int main() {
int arr[] = { 5, 3, 2, 6, 7, 1, 4 };
int n = 7, k = 3;
getLargestPermutation(arr, n, k);
for (int i = 0; i < n; ++i) {
cout << arr[i];
}
cout << endl;
return 0;
}Output
If you run the above code, then you will get the following result.
7653214
Conclusion
If you have any queries in the tutorial, mention them in the comment section.
Updated on: 09-Apr-2021
442 Views
Advertisements