ronith
10/31/2018 - 8:40 AM

Reorder an array according to given indexes

Do following for every element arr[i] While index[i] is not equal to i (i) Store array and index values of the target (or correct) position where arr[i] should be placed. The correct position for arr[i] is index[i] (ii) Place arr[i] at its correct position. Also update index value of correct position. (iii) Copy old values of correct position (Stored in step (i)) to arr[i] and index[i] as the while loop continues for i.

Reorder an array according to given indexes.cpp
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//https://www.geeksforgeeks.org/reorder-a-array-according-to-given-indexes/
#include <iostream>
using namespace std;

int main() {
    int a[] = {50, 40, 70, 60, 90};
    int index[] = {3,  0,  4,  1,  2};
    int n=5;
    int t=0;
    for (int i=0;i<n;i++) {
        while (index[i]!=i) {
            int temp1= index[index[i]];
            int temp2= a[index[i]];

            a[index[i]]= a[i];
            index[index[i]]= index[i];

            index[i]= temp1;
            a[i]= temp2;
        }
    }
    for (int i=0;i<n;i++)
        cout<< index[i]<< " "<< a[i]<< endl;
    return 0;
}