【poj1006-biorhythms】中国剩余定理

//poj1006
/*
x%23=a;
x%28=b;
x%33=c;
*/
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<iostream>
using namespace std;

int tx,ty;
/*
void exgcd(int a,int b)
{
    if(b==0) {tx=1,ty=0;return ;}
    exgcd(b,a%b);
    int x=ty,y=tx-(a/b)*ty;
    tx=x;ty=y;
}
*/
int main()
{
    freopen("a.in","r",stdin);
    freopen("a.out","w",stdout);
    int T=0;
    while(1)
    {
        int a,b,c,d;
        scanf("%d%d%d%d",&a,&b,&c,&d);    
        if(a==-1 && b==-1 && c==-1 && d==-1) return 0;
        int x=6*a*28*33;
        int y=-9*b*23*33;
        int z=2*c*23*28;
        int g=23*28*33;
        int ans=(x+y+z)%g;
        while(ans-d <= 0) ans+=g;
        while(ans-d > g) ans-=g;
        printf("Case %d: the next triple peak occurs in %d days.\n",++T,ans-d);
    }
    return 0;
}