Submission #672640

#	Time	Username	Problem	Language	Result	Execution time	Memory
672640		tbzard	Stations (IOI20_stations)	C++14	100 / 100	916 ms	756 KiB

stations

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

void dfs1(int u, int p, vector<int> &weight, vector<vector<int> > &g){
    weight[u] = 1;
    for(int i=0;i<g[u].size();i++){
        int v = g[u][i];
        if(v != p){
            dfs1(v, u, weight, g);
            weight[u] += weight[v];
        }
    }
}
void dfs2(int u, int p, int d, int l, int r, vector<int> &ans, vector<int> &weight, vector<vector<int> > &g){
    if(d%2 == 0){
        ans[u] = l;
        l++;
    }
    else{
        ans[u] = r;
        r--;
    }
    for(int i=0;i<g[u].size();i++){
        int v = g[u][i];
        if(v != p){
            dfs2(v, u, d+1, l, l+weight[v]-1, ans, weight, g);
            l += weight[v];
        }
    }
}

vector<int> label(int n, int k, vector<int> u, vector<int> v){
    vector<vector<int> > g(n);
    vector<int> weight(n);
    vector<int> ans(n);
    for(int i=0;i<n-1;i++){
        g[u[i]].push_back(v[i]);
        g[v[i]].push_back(u[i]);
    }
    dfs1(0, 0, weight, g);
    dfs2(0, 0, 0, 0, n-1, ans, weight, g);
    return ans;
}
int find_next_station(int s, int t, vector<int> c){
    if(c.size() == 1) return c[0];
    int d = 1;
    if(s < c[0]) d = 0;

    if(d){
        int p = c[0];
        if(t < c[0] || t > s) return p;
        for(int i=0;i<(int)c.size()-1;i++){
            if(c[i] <= t && t <= c[i+1]-1) return c[i];
        }
        return c[(int)c.size()-1];
    }
    else{
        int p = c[(int)c.size()-1];
        if(t < s || t > c[(int)c.size()-1]) return p;
        for(int i=1;i<(int)c.size();i++){
            if(c[i-1]+1 <= t && t <= c[i]) return c[i];
        }
        return c[0];
    }
}

Compilation message (stderr)

stations.cpp: In function 'void dfs1(int, int, std::vector<int>&, std::vector<std::vector<int> >&)':
stations.cpp:6:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    6 |     for(int i=0;i<g[u].size();i++){
      |                 ~^~~~~~~~~~~~
stations.cpp: In function 'void dfs2(int, int, int, int, int, std::vector<int>&, std::vector<int>&, std::vector<std::vector<int> >&)':
stations.cpp:23:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   23 |     for(int i=0;i<g[u].size();i++){
      |                 ~^~~~~~~~~~~~

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