Submission #565607

#	Time	Username	Problem	Language	Result	Execution time	Memory
565607		shahriarkhan	Village (BOI20_village)	C++14	50 / 100	110 ms	31948 KiB

Village

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

const int MX = 1e5 + 5 , INF = 1e9 + 5 ;

int dp[MX][2] , mn[MX] ;

vector<int> adj[MX] ;

vector<pair<int,int> > pick[MX][2] ;

void dfs(int s , int p)
{
    int sum = 0 , good = 0 , leaf = 1 , rd = 0 , pos = 0 , idx = 0 ;
    dp[s][0] = 0 , dp[s][1] = INF ;
    for(int t : adj[s])
    {
        if(t==p) continue ;
        dfs(t,s) , leaf = 0 ;
        dp[s][0] = min(dp[s][0] + dp[t][1] , INF) , pick[s][0].push_back({t,1}) ;
        if((dp[t][0]+2)<=dp[t][1])
        {
            sum += dp[t][0] + 2 , pick[s][1].push_back({t,0}) , ++pos ;
            good = 1 ;
        }
        else
        {
            if(dp[t][0]<dp[t][1])
            {
                rd = t ;
                idx = pos ;
            }
            sum += dp[t][1] , pick[s][1].push_back({t,1}) , ++pos;
        }
    }
    if(!leaf)
    {
        if(!good)
        {
            if(rd)
            {
                pick[s][1].erase(pick[s][1].begin()+idx) ;
                pick[s][1].push_back({rd,0}) ;
                sum -= dp[rd][1] ;
                sum += dp[rd][0] + 2 ;
            }
            else
            {
                pick[s][1][0].second = 2 ;
                sum += 2 ;
            }
        }
        dp[s][1] = sum ;
    }
}

void build(int s , int c)
{
    if(c==2) c = 1 ;
    for(pair<int,int> p : pick[s][c])
    {
        build(p.first,p.second) ;
        if(p.second!=1) swap(mn[p.first],mn[s]) ;
    }
}

int main()
{
    int n ;
    scanf("%d",&n) ;
    for(int i = 1 ; i < n ; ++i)
    {
        int x , y ;
        scanf("%d%d",&x,&y) ;
        adj[x].push_back(y) ;
        adj[y].push_back(x) ;
    }
    for(int i = 1 ; i <= n ; ++i)
    {
        mn[i] = i ;
    }
    dfs(1,0) ;
    build(1,1) ;
    printf("%d %d\n",dp[1][1],1) ;
    for(int i = 1 ; i <= n ; ++i)
    {
        printf("%d ",mn[i]) ;
    }
    printf("\n") ;
    for(int i = 1 ; i <= n ; ++i)
    {
        printf("%d ",1) ;
    }
    printf("\n") ;
    return 0 ;
}

Compilation message (stderr)

Village.cpp: In function 'int main()':
Village.cpp:70:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   70 |     scanf("%d",&n) ;
      |     ~~~~~^~~~~~~~~
Village.cpp:74:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   74 |         scanf("%d%d",&x,&y) ;
      |         ~~~~~^~~~~~~~~~~~~~

• Subtask 1: 6 / 12
• Subtask 2: 19 / 38
• Subtask 3: 25 / 50