题解 | 被打乱的异或和

/*
x=a^b^c^d
0=a^b^c^d^x
a=a^a^b^c^d^x
a=0^b^c^d^x
a=b^c^d^x
*/
#include<bits/stdc++.h>
using namespace std;
int main(){
    int T;
    cin>>T;
    for(int t=0;t<T;t++){
        int n;
        cin>>n;
        vector<int>a(n+2);
        int sum=0;
        for(int i=0;i<n;i++){
            
            cin>>a[i];
            sum=a[i];
        }
        printf("%d\n",sum);
    }
}

/*

x=a^b^c^d

0=a^b^c^d^x

a=a^a^b^c^d^x

a=0^b^c^d^x

a=b^c^d^x

*/