hdu2116: Has the sum exceeded

hdu2116: http://acm.hdu.edu.cn/showproblem.php?pid=2116
题意：输入k(2<=k<=64),再输入x,y(-2^(k-1)<=x,y<=2^(k-1)-1),判断x+y是否溢出(即是否超出[-2^(k-1),2^(k-1)-1])
解法：若直接相加可能溢出，所以用max-x>y和min-x<y来判断.
code：

#include<iostream>
#include<cstdio>
#include<cstdlib>
int main()
{
    long long int x,y,max,min;
    int k;
    while(scanf("%d",&k)!=EOF)
    {
        scanf("%I64d%I64d",&x,&y);
        if(k==64)
            max=0x7fffffffffffffffLL ; //2^63-1
        else
            max=(1<< (k-1)) - 1 ;             //2^(k-1)-1
        min=-max-1;                     //-2^(k-1)
        if(x<=0&&y>=0||x>=0&&y<=0)
            printf("WaHaHa\n");
        else if(x>0)
        {
            if(max-x>=y)
                printf("WaHaHa\n");
            else
                printf("Yes\n");
        }
        else
        {
            if(min-x<=y)
                printf("WaHaHa\n");
            else
                printf("Yes\n");
        }
    }
}
/*input:
32
100 100
output:
WaHaHa
*/