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답안 #388624

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
388624 2021-04-12T09:36:11 Z phathnv Svjetlo (COCI20_svjetlo) C++11
30 / 110
 391 ms 85396 KB 
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;

const int N = 5e5 + 7;

int n, dp[N][2][3], nxtDp[2][3], cnt[N];
string s;
vector<int> adj[N];

void Dfs(int u, int p){
    int state = s[u] - '0';
    cnt[u] = (state == 0);
    for(int v : adj[u]){
        if (v == p)
            continue;
        Dfs(v, u);
        cnt[u] += cnt[v];
    }
    if (cnt[u] == 0)
        return;

    dp[u][state ^ 1][0] = 1;
    dp[u][state ^ 1][1] = 1;
    dp[u][state ^ 1][2] = 1;
    for(int v : adj[u]){
        if (v == p || cnt[v] == 0)
            continue;
        memset(nxtDp, 0x3f, sizeof(nxtDp));

        for(int s = 0; s < 2; s++){
            nxtDp[s][0] = min(nxtDp[s][0], dp[u][s][1] + dp[v][1][1]);
            nxtDp[s][0] = min(nxtDp[s][0], dp[u][s ^ 1][1] + dp[v][0][1] + 2);
            nxtDp[s][0] = min(nxtDp[s][0], dp[u][s][2] + dp[v][0][0] + 1);
            nxtDp[s][0] = min(nxtDp[s][0], dp[u][s ^ 1][0] + dp[v][1][2] + 1);

            nxtDp[s][1] = min(nxtDp[s][1], dp[u][s ^ 1][1] + dp[v][1][2] + 1);
            nxtDp[s][1] = min(nxtDp[s][1], dp[u][s][1] + dp[v][0][2] + 3);
            nxtDp[s][1] = min(nxtDp[s][1], dp[u][s][2] + dp[v][1][1]);
            nxtDp[s][1] = min(nxtDp[s][1], dp[u][s ^ 1][2] + dp[v][0][1] + 2);

            nxtDp[s][2] = min(nxtDp[s][2], dp[u][s ^ 1][2] + dp[v][1][2] + 1);
            nxtDp[s][2] = min(nxtDp[s][2], dp[u][s][2] + dp[v][0][2] + 3);
        }

        for(int s = 0; s < 2; s++)
            for(int i = 1; i >= 0; i--)
                nxtDp[s][i] = min(nxtDp[s][i], nxtDp[s][i + 1]);
        for(int s = 0; s < 2; s++)
            for(int i = 0; i < 3; i++)
                dp[u][s][i] = nxtDp[s][i];
    }
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    cin >> n >> s;
    s = '*' + s;
    for(int i = 1; i < n; i++){
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }

    memset(dp, 0x3f, sizeof(dp));
    int root = 1;
    while (s[root] == '1')
        root++;
    Dfs(root, -1);
    cout << dp[root][1][0];

    return 0;
}

Subtask #1
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 12 ms 23756 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #2
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 261 ms 60276 KB Output is correct
2 Correct 385 ms 80280 KB Output is correct
3 Correct 374 ms 85396 KB Output is correct
4 Correct 347 ms 62688 KB Output is correct
5 Correct 391 ms 70328 KB Output is correct

Subtask #3
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 295 ms 38092 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 12 ms 23756 KB Output isn't correct
2 Halted 0 ms 0 KB -