题目:Biorhythms
思路: 扩展欧几里得
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
#include <cstdio> #include <iostream> #include <cstring> #include <algorithm> #include <cmath> #include <cstdlib> #include <map> using namespace std; int w[4]={0,23,28,33},a[4]; long long exgcd(long long a,long long b,long long &x,long long &y) { if(b==0) { x=1; y=0; return a; } else { long long ans=exgcd(b,a%b,x,y); long long t=x; x=y; y=t-a/b*y; return ans; } } int CRT(int r) { long long M=1; long long i,d,x0,y0,ans=0; for(i=1;i<=r;i++) M*=w[i];//好像很容易溢出的样子,CRT弱爆了 for(i=1;i<=r;i++) { d=M/w[i]; exgcd(d,w[i],x0,y0); ans=(ans+d*x0*a[i])%M; } while(ans<= 0) ans+=M; return ans; } int main() { int ca=0; int d; while(scanf("%d%d%d%d",&a[1],&a[2],&a[3],&d)!=EOF) { if(a[1]==-1&&a[2]==-1&&a[3]==-1&&d==-1) break; int M=1; for(int i=1;i<=3;i++) M*=w[i]; int ans=CRT(3); ans-=d; while(ans<=0) ans+=M; printf("Case %d: the next triple peak occurs in %d days. ",++ca,ans); } return 0; }