Submission #993514

#	Time	Username	Problem	Language	Result	Execution time	Memory
993514		lazar3141	Rack (eJOI19_rack)	C++14	0 / 100	1 ms	348 KiB

rack

#include<bits/stdc++.h>

using namespace std;

#define int long long

void dfs(int u, vector<vector<int>> &e, vector<int> &d){
    d[u] = 1;
    for(int i = 0;i<e[u].size();i++){
        int v = e[u][i];
        if(d[v]!=-1) continue;
        dfs(v, e, d);
        d[u]+=d[v];
    }
}

void dfs2(int u, int p, vector<vector<int>> &e, vector<int> &dp, vector<int> &d){
    dp[u] = 0;
    for(int i = 0;i<e[u].size();i++){
        int v = e[u][i];
        if(v==p) continue;
        dp[u] = max(dp[u], d[v]-1);
        dfs2(v, u, e, dp, d);
        int s = 0;
        for(int j = 0;j<e[u].size();j++){
            if(j==i) continue;
            int w = e[u][j];
            if(w==p) continue;
            s+=d[w]-1;
        }
        dp[u] = max(dp[u], dp[v]+s);
    }
}

void solve(){
    int n;cin>>n;
    vector<vector<int>> e(n);
    for(int i = 0;i<n-1;i++){
        int u, v;cin>>u>>v;u--;v--;
        e[u].push_back(v);
        e[v].push_back(u);
    }
    vector<int> d(n, -1);
    dfs(0, e, d);
    vector<int> dp(n, -1);
    dfs2(0, -1, e, dp, d);
    cout<<dp[0]<<endl;
    return;
}

int32_t main(){
    cin.tie(0);
    cout.tie(0);
    ios_base::sync_with_stdio(false);
    int t = 1;
    cin>>t;
    while(t--){
        solve();
    }
    return 0;
}

Compilation message (stderr)

rack.cpp: In function 'void dfs(long long int, std::vector<std::vector<long long int> >&, std::vector<long long int>&)':
rack.cpp:9:20: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    9 |     for(int i = 0;i<e[u].size();i++){
      |                   ~^~~~~~~~~~~~
rack.cpp: In function 'void dfs2(long long int, long long int, std::vector<std::vector<long long int> >&, std::vector<long long int>&, std::vector<long long int>&)':
rack.cpp:19:20: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   19 |     for(int i = 0;i<e[u].size();i++){
      |                   ~^~~~~~~~~~~~
rack.cpp:25:24: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   25 |         for(int j = 0;j<e[u].size();j++){
      |                       ~^~~~~~~~~~~~

• Subtask 1: 0 / 20
• Subtask 2: 0 / 20
• Subtask 3: 0 / 60