Submission #1274224

#	Time	Username	Problem	Language	Result	Execution time	Memory
1274224		trinm01	Power Plant (JOI20_power)	C++20	100 / 100	88 ms	21348 KiB

power

// #pragma GCC optimize("O3")
// #pragma GCC optimization("Ofast,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <bits/stdc++.h>
using namespace std;

#define int long long 
#define ll long long
#define FOR(i, l, r) for (int i = (l); i <= (r); i++)
#define FOD(i, r, l) for (int i = (r); i >= (l); i--)
#define fi first
#define se second
#define pii pair<int, int>

const ll mod = 1e9 + 7;
const int MAXN = 2e5 + 5;
const ll oo = 1e18 + 7;  
const int base = 10;

int n;
vector<int> adj[MAXN];
string s;

int ans=0;
int f[MAXN];
void dfs(int u, int p){
	for(int v:adj[u]){
		if(v==p) continue;
		dfs(v, u);
	}
	int mx=0;
	for(auto v:adj[u]){
		if(v==p) continue;
		f[u]+=f[v];
		mx=max(mx, f[v]);
	}
	if(s[u]=='1'){	
		ans=max(ans, mx+1);
		f[u]--;
		ans=max(ans, f[u]);
		f[u]=max(1LL, f[u]);
	}
	ans=max(ans, f[u]);
}

signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    
    
    // freopen("test.txt", "r", stdin);
    // freopen("o2.out", "w", stdout);

    if(fopen(".inp", "r")){
        freopen(".inp", "r", stdin);
        freopen(".out", "w", stdout);
    }

    cin >> n;
    FOR(i, 1, n-1){
    	int u, v;
    	cin >> u >> v;
    	adj[u].push_back(v);
    	adj[v].push_back(u);
    }
    cin >> s;
    s="."+s;
    
    dfs(1, 0);
    
    // cout << f[3] << ' ';
    cout << ans;
    
    return 0;
}

Compilation message (stderr)

power.cpp: In function 'int main()':
power.cpp:56:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   56 |         freopen(".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~
power.cpp:57:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   57 |         freopen(".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~

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