GCD (Greatest Common Divisor)

欧几里德算法（GCD），又称辗转相除法。

//代码一：
int gcd(int a, int b){
     return b ? gcd(b, a%b):a;
}

//代码二：
int gcd(int a, int b){
	while((a %= b) && (b %= a)) ;
	return a + b;
}

练习题：1、Uva 10193 All
you need is love //P.S.The Beatles的歌名《All You
Need Is Love》。

//扯了一大堆，原来就是求两个数是否互质。。

#include <iostream>
#include <cstring>
using namespace std;
int gcd(int a,int b){
	return b? gcd(b, a%b):a;
}
int main()
{
	int a, b;
	int T;
	char s[32];
	int i, n;
	cin>>T;n=1;
	while(n<=T){
		cout<<"Pair #"<<n++<<": ";
		cin>>s;
		a = 0;
		for(i=0;s[i];++i){
			a =a*2+s[i]-'0';
		}
		cin>>s;
		b = 0;
		for(i=0;s[i];++i){
			b =b*2+s[i]-'0';
		}
		if(gcd(a,b)==1) 
			cout<<"Love is not all you need!\n";
		else
			cout<<"All you need is love!\n";
	}
	return 0;
}