NYOJ420 p次方求和 快速幂取模

原题链接

复杂度O(logn);

#include <cstdio>#define mod 10003int f(int a, int n){if(n == 0) return 1 % mod;if(n == 1) return a % mod;int t = f(a, n / 2);t = t * t % mod;if(n & 1) return t * a % mod;return t;}int main(){int t, a, n, s, i;scanf("%d", &t);while(t-- && scanf("%d%d", &n, &a)){for(i = 1, s = 0; i <= n; ++i)s += f(i, a), s %= mod;printf("%d\n", s);}return 0;}