Submission #793146

#	Time	Username	Problem	Language	Result	Execution time	Memory
793146		anton	Power Plant (JOI20_power)	C++17	0 / 100	3 ms	4948 KiB

power

#include<bits/stdc++.h>

using namespace std;
#define int long long

const int MAX_N = 2*1e5;
int n, dp[MAX_N][2];
string s;
vector<int> adj[MAX_N];

void dfs(int id, int anc){
    for(int i = 0; i<adj[id].size(); i++){
        if(adj[id][i] == anc){
            adj[id].erase(adj[id].begin() +i);
            break;
        }
    }

    for(auto e: adj[id]){
        dfs(e, id);
    }
}


void find_dp(int id){
    dp[id][0]= 0;
    dp[id][1] = 0;

    bool gen = s[id] == '1';

    int s1=0;
    int best1= 0;
    int best0= 0;

    for(auto e: adj[id]){
        find_dp(e);
        s1 += dp[e][1];
        best1 = max(best1, dp[e][1]);
        best0 = max(best0, dp[e][0]);
    }
    if(!gen){
        dp[id][0] = max(max(s1, best0), 0LL);
        dp[id][1] = max(s1, 0LL);
    }
    else{
        dp[id][0] = max(s1-1, best1+1);
        dp[id][1] = max(s1-1, 1LL);
    }

    //cout<<id<<" "<<dp[id][0]<<" "<<dp[id][1]<<endl;
}


signed main(){
    cin>>n;

    for(int i = 0; i<n-1; i++){
        int a, b;
        cin>>a>>b;
        a--;b--;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }

    dfs(0, -1);

    cin>>s;

    find_dp(0);
    cout<<dp[0][0]<<endl;
}

Compilation message (stderr)

power.cpp: In function 'void dfs(long long int, long long int)':
power.cpp:12:21: 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]
   12 |     for(int i = 0; i<adj[id].size(); i++){
      |                    ~^~~~~~~~~~~~~~~

• Subtask 1: 0 / 6
• Subtask 2: 0 / 41
• Subtask 3: 0 / 53