Submission #550647

#	Time	Username	Problem	Language	Result	Execution time	Memory
550647		krit3379	Stations (IOI20_stations)	C++17	100 / 100	814 ms	5528 KiB

stations

#include<bits/stdc++.h>
using namespace std;
#include"stations.h"
#define N 100005

int st[N],en[N],cnt[N],sz;
vector<int> g[N];

void dfs(int s,int f,int c){
    st[s]=sz++;
    cnt[s]=c;
    for(auto x:g[s]){
        if(x==f)continue;
        dfs(x,s,c+1);
    }
    en[s]=sz++;
}

vector<int> label(int n, int k, vector<int> u, vector<int> v){
    int i,a,b,c=0;
    vector<int> vec;
    for(i=0;i<n;i++)g[i].clear(),sz=0;
    for(i=0;i<n-1;i++){
        a=u[i],b=v[i];
        g[a].push_back(b);
        g[b].push_back(a);
    }
    dfs(0,-1,1);
    map<int,int> mp;
    for(i=0;i<n;i++)mp[cnt[i]%2?st[i]:en[i]];
    for(auto &[x,y]:mp)y=c++;
    for(i=0;i<n;i++)vec.push_back(mp[cnt[i]%2?st[i]:en[i]]);
    return vec;
}

int find_next_station(int s, int t,vector<int> c){
    if(c[0]>s){
        //s->st
        if(t<s)return c.back();
        for(auto x:c)if(t<=x)return x;
        return c.back();
    }
    else{
        //s->en
        if(t>s)return c[0];
        for(int i=c.size()-1;i>=0;i--)if(t>=c[i])return c[i];
        return c[0];
    }
}

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