求2个数的最大公约数 - 轮除法
public class C1{
   public int getCommonDivisior(int a, int b){
		int temp;
		if(a<=b){
			temp = b;
			b = a;
			a = temp;
		}
		
		while (b!=0){
			temp = a%b; a=b; b = temp;
		}
		
		return a;
  }

}