oj.uz

Submission #1024536

# Submission time Handle Problem Language Result Execution time Memory
1024536 2024-07-16T07:05:24 Z stdfloat Torrent (COI16_torrent) C++17
31 / 100
 2000 ms 20708 KB 
#include <bits/stdc++.h>
using namespace std;

using ll = long long;

vector<bool> vis;

vector<int> pr;

vector<vector<int>> E;

void dfs_pr(int x, int p = -1) {
    pr[x] = p;
    for (auto i : E[x]) {
        if (i != p) dfs_pr(i, x);
    }
}

int dfs(int x) {
    vis[x] = true;

    vector<int> v;
    for (auto i : E[x]) {
        if (!vis[i]) v.push_back(dfs(i));
    }

    sort(v.rbegin(), v.rend());

    int mx = 0;
    for (int i = 0; i < (int)v.size(); i++) mx = max(mx, v[i] + i + 1);

    return mx;
}

int main() {
    ios::sync_with_stdio(false); cin.tie(nullptr);

    int n, a, b;
    cin >> n >> a >> b; a--; b--;

    E.assign(n, {});
    for (int i = 1; i < n; i++) {
        int x, y;
        cin >> x >> y;
        
        E[--x].push_back(--y);
        E[y].push_back(x);
    }

    pr.assign(n, 0);
    dfs_pr(a);

    int cur = pr[b], mn = INT_MAX;
    while (cur != -1) {
        vis.assign(n, false);

        vis[cur] = vis[b] = true;
        int x = dfs(b);

        vis[a] = true;
        vis[cur] = false;

        mn = min(mn, max(x, dfs(a)));

        cur = pr[cur];
    }

    cout << mn;
}

Subtask #1
31.0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 348 KB Output is correct
2 Correct 2 ms 504 KB Output is correct
3 Correct 5 ms 348 KB Output is correct

Subtask #2
0 / 69.0

# Verdict Execution time Memory Grader output
1 Execution timed out 2066 ms 20708 KB Time limit exceeded
2 Halted 0 ms 0 KB -