Submission #626758

#	Time	Username	Problem	Language	Result	Execution time	Memory
626758		MatBad	Power Plant (JOI20_power)	C++14	100 / 100	179 ms	30236 KiB

power

#include<bits/stdc++.h>
//#pragma GCC optimize ("O2,unroll-loops")
#pragma GCC optimize("no-stack-protector,fast-math")
using namespace std;
#define F first
#define S second
#define pb push_back
#define ppb pop_back
#define lb lower_bound
#define ub upper_bound
#define pc __builtin_popcount
#define cl __builtin_clz
#define FOR(i,a,b) for(int i=a;i<=b;i++)
#define FORR(i,a,b) for(int i=a;i>=b;i--)
#define debug(x) cerr<<#x<<" : &"<<x<<"&\n"
#define wall() cerr<<'\n'<<"-------------------------------\n"
typedef long long ll;
typedef long double ld;
typedef pair<int , int> pii;
typedef pair<bool , pii> piii;

const int
	MX=2e5+5,
	M=600,
	MOD = 1e9+7, 
	inf = 1e9+20, 
	//infl = 1e16,
	LOG = 18,
	A = 27,
	del = 10067;

int n, dp[MX][3];
bool mark[MX];
vector<int> adj[MX];

// 0: vasat valid, 1: marz=vasat invalid, 2: birun

void dfs(int u, int p=0){
	int cnt=0;
	dp[u][0] = -mark[u];
	dp[u][1] = -inf;
	for(int v:adj[u]) if(v!=p) {
		dfs(v, u);
		if(max(max((mark[v]?1:-inf), dp[v][0]), dp[v][1]-2*mark[v])>-inf){
			cnt++;
			dp[u][0]+=max(max((mark[v]?1:-inf), dp[v][0]), dp[v][1]-2*mark[v]);
		}
		dp[u][1] = max(dp[u][1], mark[u]+max(max((mark[v]?1:-inf), dp[v][0]), dp[v][1]-2*mark[v]));
		dp[u][2] = max(max(dp[u][2], dp[v][0]), max(dp[v][2], (mark[v]?dp[v][1]:-inf))); 
		dp[u][2] = max(dp[u][2], (int)mark[v]);
	}
	if(cnt<2) dp[u][0] = -inf;
}

int main(){
    ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
	cin>>n;
	FOR(i, 1, n-1){
		int u, v;
		cin>>u>>v;
		adj[u].pb(v);
		adj[v].pb(u);
	}
	FOR(i, 1, n){
		char c;
		cin>>c;
		mark[i] = c=='1';
	}
	dfs(1);
	int res=0;
	res = max(dp[1][0], res);
	res = max(dp[1][2], res);
	if(mark[1]) res = max(res, dp[1][1]);
	if(mark[1] and !res) res=1;
	cout<<res<<'\n';
}

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