Submission #1017338

#	Time	Username	Problem	Language	Result	Execution time	Memory
1017338		vjudge1	The Xana coup (BOI21_xanadu)	C++17	5 / 100	1085 ms	10588 KiB

xanadu

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

#define int long long
#define FOR(i, a, b) for (int i = (a); i <= (b); i++)
#define FORD(i, a, b) for (int i = (b); i >= (a); i --)
#define REP(i, n) for (int i = 0; i < (n); ++i)
#define REPD(i, n) for (int i = (n) - 1; i >= 0; --i)

#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)


constexpr ll LINF = (1ll << 60);
constexpr int INF = (1ll << 30);
constexpr int Mod = 1e9 + 7;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

/*
    Phu Trong from Nguyen Tat Thanh High School for gifted student
*/

template <class X, class Y>
    bool minimize(X &x, const Y &y){
        X eps = 1e-9;
        if (x > y + eps) {x = y; return 1;}
        return 0;
    }

template <class X, class Y>
    bool maximize(X &x, const Y &y){
        X eps = 1e-9;
        if (x + eps < y) {x = y; return 1;}
        return 0;
    }
#define MAX         200005
int numNode;
vector<int> G[MAX];
int label[MAX];

void process(void){
    cin >> numNode;
    for (int i = 1; i < numNode; ++i){
        int u, v; cin >> u >> v;
        --u, --v;
        G[u].emplace_back(v);
        G[v].emplace_back(u);
    }
    for (int i = 0; i < numNode; ++i) cin >> label[i];

    int ans = INF;
    vector<int> col;
    col.resize(numNode);

    auto press = [&](int x) -> void{
        col[x] ^= 1;
    };
    for (int msk = 0; msk < MASK(numNode); ++msk){
        for (int i = 0; i < numNode; ++i) col[i] = label[i];
        for (int i = 0; i < numNode; ++i) if(BIT(msk, i)){
            press(i);
            for (int&v : G[i]) press(v);
        }
        int sm = accumulate(col.begin(), col.end(), 0);
        if(!sm) minimize(ans, __builtin_popcount(msk));
    }
    if(ans >= INF) return void(cout << "impossible");
    cout << ans;
}
signed main(){
    #define name "Whisper"
    cin.tie(nullptr) -> sync_with_stdio(false);
    //freopen(name".inp", "r", stdin);
    //freopen(name".out", "w", stdout);

    process();
}

• Subtask 1: 5 / 5
• Subtask 2: 0 / 15
• Subtask 3: 0 / 10
• Subtask 4: 0 / 40
• Subtask 5: 0 / 30