Data Structure Array: Given an array arr[], find the maximum j – i such that arr[j] > arr[i]

http://www.geeksforgeeks.org/given-an-array-arr-find-the-maximum-j-i-such-that-arrj-arri/

#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
#include <stack>
#include <string>
#include <fstream>
#include <map>
using namespace std;

int maxindexdiff(int arr[], int n) {
    vector<int> L(n), R(n);
    L[0] = arr[0];
    for (int i = 1; i < n; i++) L[i] = min(L[i-1], arr[i]);
    R[n-1] = arr[n-1];
    for (int i = n-2; i >= 0; i--) R[i] = max(R[i+1], arr[i]);
    int left, right, ans;
    left = right = 0;
    ans = -1;
    while (left < n && right < n) {
        if (L[left] < R[right]) {
            ans = max(ans, right - left);
            right++;
        }
        else left++;
    }
    return ans;
}

int main() {
    int arr[10] = {9, 2, 3, 4, 5, 6, 7, 8, 18, 0};
    cout << maxindexdiff(arr, 10) << endl;
    return 0;
}