P1366有序表的合并

#include<bits/stdc++.h>
using namespace std;
int sum=0;
int main(){
	int T;
	scanf("%d",&T);
	while(T--){
 	    int n,m;
 	    unsigned long long a[10000005]={},b[10000005]={};
		scanf("%lld%lld",&n,&m);
		memset(a,0,sizeof(a));
		memset(b,0,sizeof(b));
		for(int i=1;i<=n;i++)scanf("%llu",&a[i]);
		for(int i=1;i<=m;i++)scanf("%llu",&b[i]);
		int ii=0,ans=0;
		for(int i=1;i<=n;i++){
		    ans=0;
			while(ii+1<=m&&b[ii+1]<=a[i]){
				ii++;
				if(b[ii]==a[i])ans++;	
			}
			sum^=ans;
		}
		printf("%d\n",sum);
		sum=0;
	}
	return 0;
}