Submission #960959

#	Time	Username	Problem	Language	Result	Execution time	Memory
960959		ach00	The Xana coup (BOI21_xanadu)	C++14	100 / 100	203 ms	57504 KiB

xanadu

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define INF 1000000
#define DP dp[p][s][v]
vector<bool> state;
vector<vector<int>> adj;
vector<vector<vector<int>>> dp(2, vector<vector<int>>(2, vector<int>(100005, -1)));
ll solve(int p, int s, int v, int parent) {
    if(DP != -1) return DP;
    vector<vector<ll>> temp(2, vector<ll>(2));
    temp[0][0] = 0;
    temp[1][0] = 0;
    temp[0][1] = INF;
    temp[1][1] = INF;
    for(auto &u : adj[v]) {
        if(u == parent) continue;
        vector<vector<ll>> ntemp(2,vector<ll>(2));
        ntemp[0][0] = min(solve(0, 0, u, v) + temp[0][0], solve(0, 1, u, v) + temp[0][1]);
        ntemp[0][1] = min(solve(0, 0, u, v) + temp[0][1], solve(0, 1, u, v) + temp[0][0]);
        ntemp[1][0] = min(solve(1, 0, u, v) + temp[1][0], solve(1, 1, u, v) + temp[1][1]);
        ntemp[1][1] = min(solve(1, 0, u, v) + temp[1][1], solve(1, 1, u, v) + temp[1][0]);
        temp = ntemp;
    }
    if((state[v] + s + p)&1 == 1) {
        DP = s + temp[s][1];
    } else {
        DP = s + temp[s][0];
    }
    return DP;
}

int main() {
    int n; cin >> n;
    adj.resize(n+2);
    state.resize(n+2);
    for(int i = 1; i < n; i++) {
        int a,b; cin >> a >> b;
        a--; b--;
        adj[b].push_back(a);
        adj[a].push_back(b);
    }
    for(int i = 0; i < n; i++) {
        int a; cin >> a;
        if(a) state[i] = true;
        else state[i] = false;
    }
    long long ans = min(solve(0, 0, 0, -1), solve(0, 1, 0, -1));
    if(ans >= INF) {
        cout << "impossible";
    } else {
        cout << ans;
    }
}

Compilation message (stderr)

xanadu.cpp: In function 'long long int solve(int, int, int, int)':
xanadu.cpp:25:29: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
   25 |     if((state[v] + s + p)&1 == 1) {
      |                           ~~^~~~

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