例题10-1 UVa11582 Colossal Fibonacci Numbers!（同余与模算术）

题意：

看白书

要点：

先斐波那契数列打个表，然后用同余与模算术，找个规律就行。注意数的最大值为2^64，用long long型还不够，必须要用unsigned long long型。

#include<stdio.h>#include<stdlib.h>#include<string.h>#include<math.h>int fibo[1025][8000];int g[1025];int pow_mod(unsigned long long a,unsigned long long n, int m)//注意2^64要用unsigned long long型{if (n == 0) return 1;int x = pow_mod(a, n / 2, m);unsigned long long ans =(unsigned long long)x*x%m;if (n % 2 == 1)ans = ans*a%m;return (int)ans;}int main(){unsigned long long a, b;int n,t,i,x;for (n = 2; n <= 1000; n++){fibo[n][0] = 0; fibo[n][1] = 1;for (i = 2;; i++){fibo[n][i] = (fibo[n][i - 1] % n + fibo[n][i - 2] % n) % n;if (fibo[n][i] == 1 && fibo[n][i - 1] == 0)//出现一样的说明重复了{g[n] = i-1;break;}}}scanf("%d", &t);while (t--){scanf("%llu%llu%d", &a, &b, &n);if (a == 0 || n == 1)//n=1时前面没打表,g[1]=0会REprintf("0\n");else{x = pow_mod(a%g[n], b, g[n]);printf("%d\n", fibo[n][x]);}}return 0;}