#include<bits/stdc++.h> using namespace std; int main() { int n; cin >> n; while (n--) { long long a[100001] = { 0 }; int m; cin >> m; for (int i = 0; i < m; i++) { int x; cin >> x; a[x]++; } long long s[100001] = { 0 }; for (int i = 0; i <= 100001; i++) { if (a[i]%2!=0) { s[i]=1; } } long long b; for (int i = 0; i < 100001; i++) { if (s[i]) { b = i; s[i] = 0; break; } } for (int i = 0; i < 100001; i++) { if (s[i]) { b ^= i; } } cout << b << endl; } } |
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