Submission #908530

#	Time	Username	Problem	Language	Result	Execution time	Memory
908530		arashMLG	Power Plant (JOI20_power)	C++17	100 / 100	156 ms	42016 KiB

power

#include<bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll>   pll;
 
const int N = 5e5 + 23;
const ll inf = 1e18;
 
#define F                  first
#define S                  second
#define pb	               push_back
#define sz(x)              ((int)x.size())
#define kill(x)            cout<<x , exit(0);
#define all(x)             x.begin(),x.end()
#define lc                 (v<<1)
#define rc                 ((v<<1)|1)
#define debug(x)           cerr<< #x << " : " << x << '\n';
#define int               	ll
 
int n;
int dp[N][2];
vector<int> G[N];
bool is[N];
 
void dfs(int v,int p=-1) {
	int sum0 = 0,sum1 = 0,mx1=0,mx0=0;
	for(int u : G[v]) if(u != p) {
		dfs(u,v);
		sum0 += dp[u][0];
		sum1 += dp[u][1];
		mx1= max(mx1,dp[u][1]);
		mx0=max(mx0,dp[u][0]);
	}
	
	if(is[v]) {
		dp[v][0] = max({mx0,sum1- 1,1 + mx1});
	} else {
		dp[v][0] = max({mx0,sum1});
	}
	if(is[v]) {
		dp[v][1] = max({1LL,sum1-1});
	} else {
		dp[v][1] = sum1;
	}
	
}
 
int32_t main() {
	cin.tie(nullptr)->sync_with_stdio(false);
	cin>>n;
	for(int i = 1; i< n ; i++) {
		int v,u; cin>>v>>u;
		G[v].pb(u);
		G[u].pb(v);
	}
	for(int i = 1; i <= n ; i++) {
		char c; cin>>c;
		is[i] = (c == '1');
	}
	int ans =0;
	dfs(1);
	cout<<dp[1][0] << '\n';
	return 0;
}

Compilation message (stderr)

power.cpp: In function 'int32_t main()':
power.cpp:62:6: warning: unused variable 'ans' [-Wunused-variable]
   62 |  int ans =0;
      |      ^~~

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