[51nod p2653] interval XOR [bit operation]

$link$

analysis ：

Record $[1,b]$ and $[1,a-1]$ Exclusive or values $A,B$ And prefixes and similar The answer is $AxorB$

CODE：

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#define reg register
using namespace std;
typedef long long ll;
int a,b,ans,ans2;
int main(){
    
	scanf("%d%d",&a,&b);
	for(int i=1;i<=b;i++) ans^=i;
	for(int i=1;i<a;i++) ans2^=i;
	printf("%lld",ans^ans2);	
	return 0;
}