You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
45 lines
1.2 KiB
C++
45 lines
1.2 KiB
C++
#define _CRT_SECURE_NO_WARNINGS
|
|
#define _SILENCE_CXX17_C_HEADER_DEPRECATION_WARNING
|
|
|
|
#include <bits/stdc++.h>
|
|
|
|
using namespace std;
|
|
const int N = 500500;
|
|
int a[N], deg[N];
|
|
|
|
int main() {
|
|
int T, n, m;
|
|
scanf("%d", &T);
|
|
while (T--) {
|
|
memset(deg, 0, sizeof(deg));
|
|
scanf("%d%d", &n, &m);
|
|
for (int i = 1; i <= n; i++)
|
|
scanf("%d", a + i);
|
|
for (int i = 1, u, v; i <= m; i++)
|
|
scanf("%d%d", &u, &v), deg[u]++, deg[v]++;
|
|
int cnt2[2] = {0};
|
|
for (int i = 1; i <= n; i++)
|
|
cnt2[deg[i] & 1]++;
|
|
if (cnt2[1] == 0) {
|
|
int ans1 = 0;
|
|
for (int i = 1; i <= n; i++)
|
|
if (((deg[i] + 1) / 2) & 1)
|
|
ans1 ^= a[i];
|
|
int ans2 = 0;
|
|
for (int i = 1; i <= n; i++) ans2 = max(ans2, a[i] ^ ans1);
|
|
printf("%d\n", ans2);
|
|
continue;
|
|
}
|
|
if (cnt2[1] == 2) {
|
|
int ans = 0;
|
|
for (int i = 1; i <= n; i++)
|
|
if (((deg[i] + 1) / 2) & 1)
|
|
ans ^= a[i];
|
|
printf("%d\n", ans);
|
|
continue;
|
|
}
|
|
puts("Impossible");
|
|
}
|
|
return 0;
|
|
}
|