Submission #1272472

#	Time	Username	Problem	Language	Result	Execution time	Memory
1272472		thuhienne	Cats or Dogs (JOI18_catdog)	C++20	38 / 100	3093 ms	4812 KiB

catdog

#include <bits/stdc++.h>
using namespace std;

const int INF = 1e9;

int N;
vector<int> adj[100009];
int type_pet[100009];     // 0 = none, 1 = cat, 2 = dog
int dp[100009][2];

void dfs(int u, int p) {
    dp[u][0] = dp[u][1] = 0;
    for (int v : adj[u]) if (v != p) {
        dfs(v, u);
        dp[u][0] += min(dp[v][0], dp[v][1] + 1);
        dp[u][1] += min(dp[v][1], dp[v][0] + 1);
    }
    if (type_pet[u] == 1) dp[u][1] = INF; // b?t bu?c là cat
    if (type_pet[u] == 2) dp[u][0] = INF; // b?t bu?c là dog
}

int compute_danger() {
    dfs(1, -1);
    return min(dp[1][0], dp[1][1]);
}

// ========== Các hàm theo format yêu c?u ==========

void initialize(int n, vector <int> A, vector <int> B) {
    N = n;
    for (int i = 1; i <= N; i++) {
        adj[i].clear();
        type_pet[i] = 0;
    }
    for (int i = 0; i < N - 1; i++) {
        int u = A[i], v = B[i];
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
}

int cat(int v) {
    type_pet[v] = 1;
    return compute_danger();
}

int dog(int v) {
    type_pet[v] = 2;
    return compute_danger();
}

int neighbor(int v) {
    type_pet[v] = 0;
    return compute_danger();
}

• Subtask 1: 8 / 8
• Subtask 2: 30 / 30
• Subtask 3: 0 / 62