Submission #1142400

#	Time	Username	Problem	Language	Result	Execution time	Memory
1142400		guagua0407	Power Plant (JOI20_power)	C++20	0 / 100	2 ms	4940 KiB

power

//#pragma GCC optimize("O3")
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int,int>
#define f first
#define s second
#define all(x) x.begin(),x.end()
#define _ ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

int dx[4]={0,0,1,-1};
int dy[4]={1,-1,0,0};

void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}

const int mxn=2e5+5;
vector<int> adj[mxn];
int dp[mxn];
int c[mxn];
int ans=0;

void dfs(int v,int p=0){
    dp[v]=0;
    int sum=0;
    int mx=0;
    for(auto u:adj[v]){
        if(u==p) continue;
        dfs(u,v);
        mx=max(mx,dp[u]);
        sum+=dp[u];
    }
    if(c[v]==1){
        dp[v]=max(1,sum-1);
        ans=max(ans,mx+1);
    }
    else{
        dp[v]=max(0,sum);
    }
    ans=max(ans,dp[v]);
}

int main() {_
    int n;
    cin>>n;
    for(int i=0;i<n-1;i++){
        int a,b;
        cin>>a>>b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    for(int i=1;i<=n;i++){
        char cc;
        cin>>cc;
        if(cc=='1') c[i]=1;
        else c[i]=0;
    }
    dfs(1);
    cout<<*max_element(dp+1,dp+n+1)<<'\n';
    return 0;
}
//maybe its multiset not set
//yeeorz
//diaoborz

Compilation message (stderr)

power.cpp: In function 'void setIO(std::string)':
power.cpp:15:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
power.cpp:16:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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