제출 #689949

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
689949		Patrick	경주 (Race) (IOI11_race)	C++17	9 / 100	157 ms	49880 KiB

race

#include "race.h"

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

typedef long long ll;

int GN, GK;
vector<vector<pair<int, int>>> es;
int curmin;
vector<int> parent;

unordered_map<ll, int> solve(int last, int cur) {
    // cout << "solve " << cur << endl;
    unordered_map<ll, int> ans;
    ans.insert({0, 0});

    for (auto [next, len] : es[cur]) {
        if (next == last) continue;
        unordered_map<ll, int> a = solve(cur, next);

        for (auto [k, v] : a) {
            if (k > GK) continue;
            ll search = GK - (k + (ll)len);
            auto it = ans.find(search);
            if (it != ans.end()) {
                curmin = min(curmin, it->second + v + 1);
            }
        }
        for (auto [k, v] : a) {
            if (k > GK) continue;
            ans.insert({k + (ll)len, v + 1});
        }
    }
    return ans;
}

vector<unordered_map<ll, int>> ans1;

void solve1(int cur) {
    unordered_map<ll, int>& ans = ans1[cur];
    ans.insert({0, 0});

    for (auto [next, len] : es[cur]) {
        if (next == parent[cur]) continue;
        auto& a = ans1[next];

        for (auto [k, v] : a) {
            if (k > GK) continue;
            ll search = GK - (k + (ll)len);
            auto it = ans.find(search);
            if (it != ans.end()) {
                curmin = min(curmin, it->second + v + 1);
            }
        }
        for (auto [k, v] : a) {
            if (k > GK) continue;
            ans.insert({k + (ll)len, v + 1});
        }
    }
}

int best_path(int N, int K, int H[][2], int L[]) {
    GN = N;
    GK = K;

    // rlimit rl;
    // getrlimit(RLIMIT_STACK, &rl);
    // rl.rlim_cur =
    //     max(rl.rlim_cur,
    //         (sizeof(unordered_map<ll, int>) + sizeof(int) * 2 + 20) *
    //         2000100);
    // setrlimit(RLIMIT_STACK, &rl);

    // cout << "doit " << N << endl;
    es = vector<vector<pair<int, int>>>(N);
    for (int i = 0; i < N - 1; i++) {
        es[H[i][0]].push_back({H[i][1], L[i]});
        es[H[i][1]].push_back({H[i][0], L[i]});
    }

    parent = vector<int>(N, -1);

    vector<int> stack;
    stack.push_back(0);
    vector<int> topo;
    while (stack.size()) {
        int cur = stack.back();
        stack.pop_back();
        topo.push_back(cur);
        for (auto [e, l] : es[cur]) {
            if (e != parent[cur]) {
                parent[e] = cur;
                stack.push_back(e);
            }
        }
    }

    curmin = INT_MAX;
    ans1 = vector<unordered_map<ll, int>>(N);
    for (int i = topo.size() - 1; i >= 0; i--) {
        solve1(i);
    }

    // auto ans = solve(-1, 0);
    if (curmin == INT_MAX) {
        return -1;
    } else {
        return curmin;
    }
}

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