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답안 #388626

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
388626 2021-04-12T09:48:34 Z phathnv Svjetlo (COCI20_svjetlo) C++11
110 / 110
 422 ms 91724 KB 
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;

const int N = 5e5 + 7;
const int INF = 1e9 + 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][2] + dp[v][1][0] + 3);
            nxtDp[s][0] = min(nxtDp[s][0], dp[u][s ^ 1][0] + dp[v][1][2] + 1);
            nxtDp[s][0] = min(nxtDp[s][0], dp[u][s][0] + dp[v][0][2] + 3);

            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
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 23756 KB Output is correct
2 Correct 12 ms 23756 KB Output is correct
3 Correct 12 ms 23764 KB Output is correct
4 Correct 12 ms 23784 KB Output is correct
5 Correct 12 ms 23756 KB Output is correct
6 Correct 13 ms 23756 KB Output is correct
7 Correct 12 ms 23756 KB Output is correct
8 Correct 12 ms 23712 KB Output is correct
9 Correct 14 ms 23716 KB Output is correct

Subtask #2
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 268 ms 63872 KB Output is correct
2 Correct 400 ms 86112 KB Output is correct
3 Correct 373 ms 91724 KB Output is correct
4 Correct 347 ms 66044 KB Output is correct
5 Correct 388 ms 74608 KB Output is correct

Subtask #3
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 329 ms 38040 KB Output is correct
2 Correct 384 ms 48180 KB Output is correct
3 Correct 422 ms 48820 KB Output is correct
4 Correct 307 ms 44892 KB Output is correct
5 Correct 302 ms 48416 KB Output is correct
6 Correct 271 ms 45828 KB Output is correct
7 Correct 329 ms 49104 KB Output is correct

Subtask #4
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 23756 KB Output is correct
2 Correct 12 ms 23756 KB Output is correct
3 Correct 12 ms 23764 KB Output is correct
4 Correct 12 ms 23784 KB Output is correct
5 Correct 12 ms 23756 KB Output is correct
6 Correct 13 ms 23756 KB Output is correct
7 Correct 12 ms 23756 KB Output is correct
8 Correct 12 ms 23712 KB Output is correct
9 Correct 14 ms 23716 KB Output is correct
10 Correct 268 ms 63872 KB Output is correct
11 Correct 400 ms 86112 KB Output is correct
12 Correct 373 ms 91724 KB Output is correct
13 Correct 347 ms 66044 KB Output is correct
14 Correct 388 ms 74608 KB Output is correct
15 Correct 329 ms 38040 KB Output is correct
16 Correct 384 ms 48180 KB Output is correct
17 Correct 422 ms 48820 KB Output is correct
18 Correct 307 ms 44892 KB Output is correct
19 Correct 302 ms 48416 KB Output is correct
20 Correct 271 ms 45828 KB Output is correct
21 Correct 329 ms 49104 KB Output is correct
22 Correct 350 ms 45516 KB Output is correct
23 Correct 417 ms 46708 KB Output is correct
24 Correct 352 ms 45868 KB Output is correct
25 Correct 343 ms 44572 KB Output is correct
26 Correct 367 ms 50184 KB Output is correct
27 Correct 317 ms 49972 KB Output is correct
28 Correct 272 ms 46528 KB Output is correct
29 Correct 356 ms 48788 KB Output is correct
30 Correct 321 ms 47208 KB Output is correct