#include <bits/stdc++.h>   using namespace std;   void init_code() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);   }   int main() {     init_code();     int t;     cin >> t;     while (t--) {       int n;       cin >> n;       vector<int> arr(n + 1, 0);       map<int, int> mp;       for (int i = 1; i <= n; ++i) {         cin >> arr[i];         mp[arr[i]] += 1;       }       int res = 0, shifts = 0;       for (int i = 1; i <= n; ++i) {         if (arr[i] > i + shifts) {           int diff = arr[i] - i - shifts;           res += diff;           shifts += diff;         }       }       cout << res <<   n ;     }     return 0;   }   