Hihocoder 1509 XOR sort

Here are the questions.

 

    Considering the first and second numbers x, y, we can find that S is determined only on the highest bit of (x XOR y) (if x = = y is not restricted), and we can deduce what is 1/0.

    So let’s simulate this operation and decide if there’s any contradiction in the restriction. If there’s no contradiction, the answer is 2 ^ free bit.

 

#include<bits/stdc++.h>
#define ll long long
using namespace std;

int n,ban[67];
ll now,pre,Xor,c[67],ans=1;

int main(){
	scanf("%d",&n),fill(ban,ban+60,-1);
	c[0]=1; for(int i=1;i<=60;i++) c[i]=c[i-1]+c[i-1];
	
	for(int i=1;i<=n;pre=now,i++){
		scanf("%lld",&now);
		
		if(!pre) continue;
		
		for(int j=59;j>=0;j--) if((now&c[j])^(pre&c[j])){
			if(now&c[j]){
				if(ban[j]==1){ puts("0"); return 0;}
				ban[j]=0;
			}
			else{
				if(ban[j]==0){ puts("0"); return 0;}
				ban[j]=1;					
			}
			break;
		}
	}
	
	for(int i=0;i<60;i++) if(ban[i]==-1) ans*=2ll;
	
	cout<<ans<<endl;
	return 0;
}

  

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