element-at-index-rotated.cpp

// CPP code to rotate an array 
// and answer the index query 
#include <bits/stdc++.h> 
using namespace std; 
  
// Function to compute the element at 
// given index 
int findElement(int arr[], int ranges[][2], 
               int rotations, int index) 
{ 
    for (int i = rotations - 1; i >= 0; i--) { 
  
        // Range[left...right] 
        int left = ranges[i][0]; 
        int right = ranges[i][1]; 
  
        // Rotation will not have any effect 
        if (left <= index && right >= index) { 
            if (index == left) 
                index = right; 
            else
                index--; 
        } 
    } 
  
    // Returning new element 
    return arr[index]; 
} 
  
// Driver 
int main() 
{ 
    int arr[] = { 1, 2, 3, 4, 5 }; 
  
    // No. of rotations 
    int rotations = 2; 
  
    // Ranges according to 0-based indexing 
    int ranges[rotations][2] = { { 0, 2 }, { 0, 3 } }; 
  
    int index = 1; 
  
    cout << findElement(arr, ranges, rotations, index); 
  
    return 0; 
  
}