Submission #253602

#	Time	Username	Problem	Language	Result	Execution time	Memory
253602		IgorI	Cats or Dogs (JOI18_catdog)	C++17	38 / 100	3059 ms	16376 KiB

catdog

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const int INF = 1e9;

int n;
vector<int> graph[500000];
int x[500000];

pair<int, int> calc(int v, int p)
{
    pair<int, int> ans0 = {0, 0};
    for (auto u : graph[v]) if (u != p)
    {
        pair<int, int> ans1 = calc(u, v);
        ans0.first += min(ans1.first, ans1.second + 1);
        ans0.second += min(ans1.first + 1, ans1.second);
    }
    if (x[v] == 0) ans0.second = INF;
    if (x[v] == 1) ans0.first = INF;
    return ans0;
}

void initialize(int n0, vector<int> a, vector<int> b)
{
    n = n0;
    for (int i = 0; i < n - 1; i++)
    {
        a[i]--, b[i]--;
        graph[a[i]].push_back(b[i]);
        graph[b[i]].push_back(a[i]);
    }
    for (int i = 0; i < n; i++)
    {
        x[i] = -1;
    }
}

int cat(int v)
{
    v--;
    x[v] = 0;
    return min(calc(0, 0).first, calc(0, 0).second);
}

int dog(int v)
{
    v--;
    x[v] = 1;
    return min(calc(0, 0).first, calc(0, 0).second);
}

int neighbor(int v)
{
    v--;
    x[v] = -1;
    return min(calc(0, 0).first, calc(0, 0).second);
}

#ifdef LOCAL
int main()
{
    int n;
    cin >> n;
    vector<int> a(n - 1), b(n - 1);
    for (int i = 0; i < n - 1; i++)
    {
        cin >> a[i] >> b[i];
    }
    initialize(n, a, b);
    int q;
    cin >> q;
    while (q--)
    {
        int t, v;
        cin >> t >> v;
        if (t == 1) cout << cat(v) << endl;
        if (t == 2) cout << dog(v) << endl;
        if (t == 3) cout << neighbor(v) << endl;
    }
}
#endif // LOCAL

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