Submission #1311503

#	Time	Username	Problem	Language	Result	Execution time	Memory
1311503		kawhiet	Race (IOI11_race)	C++20	9 / 100	3097 ms	13376 KiB

race

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

vector<vector<pair<int, int>>> g;
vector<map<int, int>> dp;

void dbg(map<int, int> m) {
    for (auto [x, y] : m) cerr << x << ' ' << y << '\n';
    cerr << '\n';
}

int k, res;

void dfs(int u, int p) {
    dp[u][0] = 0;
    for (auto [v, w] : g[u]) {
        if (v == p) continue;
        dfs(v, u);
        map<int, int> m;
        for (auto [len, x] : dp[v]) {
            m[len + w] = x + 1;
        }
        if (dp[u].size() > m.size()) {
            swap(dp[u], m);
        }
        auto dp_nw = dp[u];
        for (auto [len, x] : dp[u]) {
            for (auto [s, cost] : m) {
                int len_nw = s + len;
                if (!dp_nw.count(len_nw)) {
                    dp_nw[len_nw] = x + cost;
                } else {
                    dp_nw[len_nw] = min(dp_nw[len_nw], x + cost);
                }
            }
        }
        swap(dp[u], dp_nw);
        dp[v].clear();
    }
    if (dp[u].count(k)) {
        res = min(res, dp[u][k]);
    }
}

int best_path(int N, int K, int H[][2], int L[]) {
    k = K;
    g.resize(N);
    dp.resize(N);
    for (int i = 0; i < N - 1; i++) {
        int u = H[i][0], v = H[i][1], w = L[i];
        g[u].push_back({v, w});
        g[v].push_back({u, w});
    }
    res = N + 1;
    dfs(0, -1);
    return (res == N + 1 ? -1 : res);
}

• Subtask 1: 9 / 9
• Subtask 2: 0 / 12
• Subtask 3: 0 / 22
• Subtask 4: 0 / 57