HDU 5661 Claris and XOR

#include <cstdio>
#include <cmath>
#include <cstring>
#include <string>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#include <stack>
#include <map>
#include <set>
#include <vector>
#include <sstream>
#include <queue>
#include <utility>
using namespace std;

#define rep(i,j,k) for (int i=j;i<=k;i++)
#define Rrep(i,j,k) for (int i=j;i>=k;i--)

#define Clean(x,y) memset(x,y,sizeof(x))
#define LL long long
#define ULL unsigned long long
#define inf 0x7fffffff
#define mod %100000007

int T;
LL a,b,c,d;
LL ans;
LL bit[70];

bool zero(int i , LL lim , LL now)
{
return now-1>=lim-bit[i];
}
bool one(int i , LL lim , LL now)
{
return now<=lim-bit[i];
}
int main()
{
bit[1] = 1;
rep(i,2,63) bit[i] = bit[i-1]<<1;
cin>>T;
while(T--)
{
scanf("%I64d %I64d %I64d %I64d",&a,&b,&c,&d);
ans = 0;
ULL tx,ty;
tx = ty = 0;
bool x_one,x_zero;
bool y_one,y_zero;
Rrep(i,61,1)
{
x_one = one(i,b,tx);
x_zero = zero(i,a,tx);
y_one = one(i,d,ty);
y_zero = zero(i,c,ty);
if ( (x_one && y_zero) || ( x_zero && y_one )  ) //可以相异
{
ans+=bit[i];
if ( x_one && y_zero ) tx+=bit[i]; //第一个数的第i位取1
else ty+=bit[i];//第二个数的第i位取1
}
else
{
if ( x_one && y_one )//都只能取1
{
tx+=bit[i];
ty+=bit[i];
}
}
}
cout<<ans<<endl;
}
return 0;
}