Submission #595016

#	Time	Username	Problem	Language	Result	Execution time	Memory
595016		pakhomovee	Dreaming (IOI13_dreaming)	C++17	24 / 100	1088 ms	23448 KiB

dreaming

#include "dreaming.h"
#include <vector>
#include <map>
#include <deque>
#include <iostream>

using namespace std;

const int maxn = 1e5;
const int inf = 2e9;
bool used[maxn];

map<int, int> dst(int v, vector<vector<pair<int, int>>> &g) {
    map<int, int> d;
    deque<int> q;
    q.push_back(v);
    d[v] = 0;
    while (!q.empty()) {
        int v = q.front();
        q.pop_front();
        for (auto [u, w] : g[v]) {
            if (!d.count(u)) {
                d[u] = d[v] + w;
                q.push_back(u);
            }
        }
    }
    return d;
}

pair<int, int> goFar(int v, vector<vector<pair<int, int>>> &g) {
    auto d1 = dst(v, g);
    int best = v;
    for (auto [u, x] : d1) {
        if (d1[best] < x) {
            best = u;
        }
        used[u] = true;
    }
    return { best, d1[best] };
}

pair<int, int> findDiam(int v, vector<vector<pair<int, int>>> &g) {
    int leafe = goFar(v, g).first;
    int best = goFar(leafe, g).first;
    int best1 = goFar(best, g).first;
    return { best, best1 };
}

int findDiamLen(int v, vector<vector<pair<int, int>>> &g) {
    int leafe = goFar(v, g).first;
    int best = goFar(leafe, g).first;
    return goFar(best, g).second;
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    vector<vector<pair<int, int>>> g(N);
    for (int i = 0; i < M; ++i) {
        int u = A[i], v = B[i];
        g[u].push_back({ v, T[i] });
        g[v].push_back({ u, T[i] });
    }
    vector<pair<int, int>> dims;
    for (int i = 0; i < N; ++i) {
        if (!used[i]) {
            dims.push_back(findDiam(i, g));
        }
    }
    pair<int, int> curr = dims[0];
    /*cout << "OUT" << endl;
    for (auto [x, y] : dims) {
        cout << x << ' ' << y << endl;
    }*/
    for (int i = 1; i < dims.size(); ++i) {
        auto d1 = dst(curr.first, g);
        auto d2 = dst(curr.second, g);
        auto d3 = dst(dims[i].first, g);
        auto d4 = dst(dims[i].second, g);
        pair<int, int> cand;
        int b1 = inf;
        for (auto [u, l] : d1) {
            if (b1 > max(l, d2[u])) {
                b1 = max(l, d2[u]);
                cand.first = u;
            }
        }
        b1 = inf;
        for (auto [u, l] : d3) {
            if (b1 > max(l, d4[u])) {
                b1 = max(l, d4[u]);
                cand.second = u;
            }
        }
        //cout << "UNITE " << cand.first << ' ' << cand.second << endl;
        g[cand.first].push_back({ cand.second, L });
        g[cand.second].push_back({ cand.first, L });
        curr = findDiam(cand.first, g);
    }
    return findDiamLen(0, g);
}

Compilation message (stderr)

dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:74:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   74 |     for (int i = 1; i < dims.size(); ++i) {
      |                     ~~^~~~~~~~~~~~~

• Subtask 1: 14 / 14
• Subtask 2: 10 / 10
• Subtask 3: 0 / 23
• Subtask 4: 0 / 18
• Subtask 5: 0 / 12
• Subtask 6: 0 / 23