处理乘法取模爆long long 的方法

#include <iostream> #include <cstdio> #include <cstring> #include <ctime> #include <cstdlib> #include <algorithm> #include <stack> #include <cmath> #include <vector> #define eps 1e-6 #define INF 1000000007 #define PI acos(-1.0) using namespace std; long long mod = 10000000000LL; long long multi(long long a, long long b, long long c) { long long ret = 0; while(b) { if(b & 1) { ret += a; if(ret >= c) ret -= c; } a += a; if(a >= c) a -= c; b >>= 1; } return ret; } long long fastmod(long long a, long long b, long long c)//a^b mod c { long long ret = 1; a %= c; for (; b; b >>= 1, a = multi(a, a, c)) if (b & 1) ret = multi(ret, a, c); return ret; } int main() { long long sum = 0; for(int i = 1; i <= 1000; i++) sum = (sum + fastmod(i, i, mod)) % mod; cout << sum << endl; return 0; }