Problem-solving ideas
First find out all the binary digits covered by at least one animal number.
If a binary bit corresponds to a feed, but this bit is not covered by an existing animal, the newly added animal number cannot cover this bit, otherwise a new feed type will appear.
If the last x bits can be overwritten, the final answer is 2^x−n.
Special attention : need to consider the reference code of some boundary conditions
#include <bits/stdc++.h>
using namespace std;
const string str = "18446744073709551616"; const int N = 65;
bool vis[N], flag[N];
int main() {
int n, m, c, k; cin >> n >> m >> c >> k;
for (int i = 1; i <= n; ++i) {
unsigned long long x; cin >> x;
for (int j = k - 1; j >= 0; --j) {
vis[j] |= (x >> j) & 1;
}
}
for (int i = 1; i <= m; ++i) {
int p, q; cin >> p >> q;
if (!vis[p]) {
flag[p] = true;
}
}
int sum = 0;
for (int i = 0; i < k; ++i) {
if (flag[i]) {
++sum;
}
}
if (k - sum == 64) {
if (n) {
cout << (unsigned long long) -n << '\n';
} else {
cout << str << '\n';
}
} else {
cout << (1ull << (k - sum)) - n << '\n';
}
return 0;
}