北大ACM(POJ1006-Biorhythms)

Question：http://poj.org/problem?id=1006

问题点：孙子定理

 Memory: 248K        Time: 0MS
 Language: C++        Result: Accepted
 3
  #include <iostream>

 using namespace std;
 int getGCD(int a,int b)//Greatest Common Divisor
 {
     if(a<b){a+=b;b=a-b;a=a-b;}
     if(b==) return ;
     else if(a%b==) return a/b;
     else return getGCD(b,a%b);
 }
 int getLCM(int a,int b)//Lowest Common Multiple
 {
     return a*b/getGCD(a,b);
 }
 int getMod1(int a,int b)//get N. a*N mod b ==1
 {
     int N=;
     while(a*N%b!=){N++;}
     return a*N;
 }
 int main()
 {
     int p,e,i,d,cnt=;
     int pe=getMod1(getLCM(,),);
     int pi=getMod1(getLCM(,),);
     int ei=getMod1(getLCM(,),);
     while(true)
     {
         cin>>p>>e>>i>>d;
         if(p==-&&e==-&&i==-&&d==-) return ;
         int m=(ei*p+pi*e+pe*i)%(**)-d;
         if(m<=) m+=**;
         cout<<"Case "<<cnt++<<": the next triple peak occurs in "<<m<<" days."<<endl;
     }
 }