문제
풀이
#include <iostream>
using namespace std;
void solve(void) {
int n, m; cin >> n >> m;
int a, b; cin >> a >> b;
bool ans = true;
while (m--) {
int k; cin >> k;
ans ^= ((ans && a <= k) || (!ans && b <= k));
}
cout << (ans ? a : b);
}
int main(void) {
ios::sync_with_stdio(false);
cin.tie(nullptr);
solve();
return 0;
}