Submission #781061

#	Time	Username	Problem	Language	Result	Execution time	Memory
781061		kamelfanger83	Stations (IOI20_stations)	C++14	52.32 / 100	762 ms	708 KiB

stations

#include "stations.h"
#include <vector>
#include <cassert>

#define int long long

using namespace std;

vector<pair<int, int>> prepost;
vector<vector<int>> cons;
int C = 0;

void dfs(int i, int from){
    prepost[i].first = C++;
    for (int c : cons[i]){
        if (c == from) continue;
        dfs(c, i);
    }
    prepost[i].second = C - 1;
}

vector<signed> label(signed n, signed k, vector<signed> u, vector<signed> v) {
    vector<signed> labels(n);
    cons.clear();
    cons.resize(n);
    for (int i = 0; i < n - 1; ++i) {
        cons[u[i]].push_back(v[i]);
        cons[v[i]].push_back(u[i]);
    }

    prepost.clear();
    prepost.resize(n);
    C = 0;
    dfs(0, -1);

    for (int i = 0; i < n; ++i) {
        labels[i] = prepost[i].first * 1000 + prepost[i].second;
    }

    return labels;
}

signed find_next_station(signed s, signed t, vector<signed> c) {
    int spre = s / 1000, spost = s % 1000;
    int tpre = t / 1000, tpost = t % 1000;
    bool isdes = spre < tpre && tpost <= spost;
    for (int i = 0; i < c.size(); ++i) {
        int cpre = c[i] / 1000, cpost = c[i] % 1000;
        if (cpre < spre && spost <= cpost){
            if (!isdes) return c[i];
        }
        else if (cpre <= tpre && tpost <= cpost){
            assert(isdes);
            return c[i];
        }
    }
    //assert(false);
    //return 0;
}

Compilation message (stderr)

stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:47:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   47 |     for (int i = 0; i < c.size(); ++i) {
      |                     ~~^~~~~~~~~~
stations.cpp:59:1: warning: control reaches end of non-void function [-Wreturn-type]
   59 | }
      | ^

• Subtask 1: 0 / 5
• Subtask 2: 0 / 8
• Subtask 3: 16 / 16
• Subtask 4: 10 / 10
• Subtask 5: 26.3205 / 61