Submission #1063393

#	Time	Username	Problem	Language	Result	Execution time	Memory
1063393		ThylOne	Power Plant (JOI20_power)	C++14	0 / 100	3 ms	5172 KiB

power

//####################
//PowerPlant
//####################
#include<bits/stdc++.h>

using namespace std;
const int maxiN = 2*1e5;
bool isPowerPlant[maxiN];
vector<int> links[maxiN];
int dp[2][maxiN];
int solve(bool cm,int node,int dad=-1){
	if(dp[cm][node]!=-1)return dp[cm][node];
	if(cm){
		//avec malus !
		int malus = (cm && isPowerPlant[node]);
		int re = (isPowerPlant[node]);
		int sum = 0;
		for(int v:links[node])if(dad!=v){
			re = max(re, solve(1,v,node) - malus);
			sum += solve(1,v,node);
		}
		re = max(re, sum-malus);
		return dp[1][node] = re;
	}else{
		int re = (isPowerPlant[node]);
		int sum = 0;
		for(int v:links[node])if(dad!=v){
			re = max(re, solve(0,v,node));
			sum += solve(1,v,node);
		}
		re = max(re, sum);
		return dp[0][node] = re;
	}
}
signed main(){
	ios::sync_with_stdio(false);
	int n;cin>>n;
	for(int i = 1;i<n;i++){
		int a,b;cin>>a>>b;
		a--;
		b--;
		links[a].push_back(b);
		links[b].push_back(a);
	}
	fill(dp[0],dp[0]+n,-1);
	fill(dp[1],dp[1]+n,-1);
	string binary;cin>>binary;
	for(int i= 0;i<n;i++)isPowerPlant[i] = (binary[i]=='1');
	int ans = max(solve(0,0),solve(1,0));
	for(int i = 0;i<1;i++){
		if(isPowerPlant[i]){
			for(int v:links[i])if(v!=i){
				ans = max(ans, 1+solve(1,v,i));
			}
		}
	}
	cout<<ans<<endl;
	return 0;
};

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