Codeforces Round #770 (Div. 2) B. Fortune Telling

Solution

왼쪽 끝 비트가 1인지 0인지 판별해서 target과 같은지 여부를 확인하면 됨

#include <bits/stdc++.h>

#pragma optimization_level 3
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#pragma GCC optimize("Ofast")//Comment optimisations for interactive problems (use endl)
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization ("unroll-loops")

#define MAX_N 505
#define INF 987654321
#define ll long long
#define pll pair<ll, ll>
#define vpll vector<pll>
#define vall3 vector<array<ll,3>>
#define all5 array<ll,5>
#define vall5 vector<all5>
#define vll vector<ll>
#define vs vector<string>
#define usll unordered_set<ll>
#define vvs vector<vs>
#define vvll vector<vll>
#define all(a) begin(a), end(a)

using namespace std;

string solve(vll& A, ll s, ll t) {
    ll bi = 0;
    for(auto& a : A) {
        bi += (a & 1);
    }
    bi &= 1;
    s = (s & 1);
    s ^= bi;
    
    return s == (t & 1) ? "Alice" : "Bob";
}


int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.setf(ios::fixed);
    cout.precision(8);
    ll tc;
    cin >> tc;
    while(tc--) {
        ll n, s, t;
        cin>>n>>s>>t;
        vll A(n);
        for(ll i = 0; i < n; i++) cin>>A[i];
        cout<<solve(A,s,t)<<endl;
    }

    return 0;
}