fork download
copy 
  1. #include <iostream>
  2. using namespace std;
  3.  
  4. const int mod = 1e9 + 7;
  5.  
  6. int main() {
  7.     long long x, n, a = 1, b = 0;
  8.     cin >> x >> n;
  9.     for(int i = 1; i <= n; i++) {
  10.         a = a * x % mod;
  11.         if(i % 2 == 1) b = (b + a) % mod;
  12.         else b = (b - a + mod) % mod;
  13.     }
  14.     cout << b;
  15.     return 0;
  16. }
  17.  
Success #stdin #stdout 0.01s 5320KB
comments (?)
stdin
copy 
2 4
stdout
copy 
999999997
https://ideone.com/5XkKg5
language:
C++ (gcc 8.3)
created:
13 hours ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!