Biorhythms(中国剩余定理)

本篇博客就不具体讲解中国剩余定理。想要具体了解，弄懂中国剩余定理，推荐以下博客，耐心看：

https://www.cnblogs.com/kindleheart/p/8877548.html

https://blog.youkuaiyun.com/d_x_d/article/details/48466957

题目：Biorhythms

链接：http://poj.org/problem?id=1006

#include<stdio.h>
#include<string.h>
#include<iostream>
using namespace std;
#define mod 21252
void Extend_gcd(int a, int b, int &x, int &y){//扩展欧几里得算法
     if(!b){
        x = 1;
        y = 0;
        return;
     }
     Extend_gcd(b, a%b, x, y);
     int k = x;
     x = y;
     y =  k - a/b*y;
}
int CRT(int a[], int b[], int n){//中国剩余定理
    int ans = 0, x, y, M = 1, N;
    for(int i = 0; i < n; i++){
        M *= a[i];
    }
    for(int i = 0; i < n; i++){
        N = M / a[i];
        Extend_gcd(N,a[i], x, y);
        ans = (ans + N * x * b[i]) % mod;
    }

    return ans;

}
int main(){
    int a[3] = {23,28,33}, b[15];
    int d, cn = 0;
    while(scanf("%d %d %d %d", &b[0], &b[1], &b[2], &d) && d != -1){
        int k = CRT(a, b, 3)-d;
        cn++;
        if(k <= 0)k += mod;
        printf("Case %d: the next triple peak occurs in %d days.\n", cn, k);
    }

}