Reorder an array according to given indexes - GeeksforGeeks

Reorder an array according to given indexes - GeeksforGeeks

Reorder an array according to given indexes

Given two integer arrays of same size, "arr[]" and "index[]", reorder elements in "arr[]" according to given index array. It is not allowed to given array arr's length.

Example:

Input:  arr[]   = [10, 11, 12];          index[] = [1, 0, 2];  Output: arr[]   = [11, 10, 12]          index[] = [0,  1,  2]     Input:  arr[]   = [50, 40, 70, 60, 90]          index[] = [3,  0,  4,  1,  2]  Output: arr[]   = [40, 60, 90, 50, 70]          index[] = [0,  1,  2,  3,   4]   

Expected time complexity O(n) and auxiliary space O(1)

We strongly recommend you to minimize your browser and try this yourself first.

A Simple Solution is to use an auxiliary array temp[] of same size as given arrays. Traverse the given array and put all elements at their correct place in temp[] using index[]. Finally copy temp[] to arr[] and set all values of index[i] as i.

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