Submission #373219

#	Time	Username	Problem	Language	Result	Execution time	Memory
373219		AmineWeslati	Power Plant (JOI20_power)	C++14	100 / 100	239 ms	33004 KiB

power

//Never stop trying
#include "bits/stdc++.h"
using namespace std;
#define boost ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)

typedef long long ll;
typedef string str;
typedef long double ld;
typedef pair<int, int> pi;
#define fi first
#define se second
typedef vector<int> vi;
typedef vector<pi> vpi;
#define pb push_back
#define eb emplace_back
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define endl "\n"
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)

const int MOD = 1e9 + 7; //998244353
const ll INF = 1e18;
const int MX = 2e5 + 10;
const int nx[4] = {0, 0, 1, -1}, ny[4] = {1, -1, 0, 0}; //right left down up

template<class T> using V = vector<T>;
template<class T> bool ckmin(T& a, const T& b) { return a > b ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }
ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); } // divide a by b rounded up
//constexpr int log2(int x) { return 31 - __builtin_clz(x); } // floor(log2(x))

mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
//mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());
ll random(ll a, ll b){
    return a + rng() % (b - a + 1);
}
#ifndef LOCAL  
#define cerr if(false) cerr
#endif
#define dbg(x) cerr << #x << " : " << x << endl; 
#define dbgs(x,y) cerr << #x << " : " << x << " / " << #y << " : " << y << endl;
#define dbgv(v) cerr << #v << " : " << "[ "; for(auto it : v) cerr << it << ' '; cerr << ']' << endl;
#define here() cerr << "here" << endl;

void IO() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin); 
    freopen("output.txt", "w", stdout);
#endif
}
/////////////////////////ONLY CLEAN CODES ALLOWED/////////////////////////

int N; 
vi adj[MX],gen(MX),f1(MX),f2(MX);

void dfs1(int u=1, int p=0){
	int ans=gen[u];
	int s=-gen[u];
	for(auto v: adj[u]) if(v!=p){
		dfs1(v,u);
		s+=f1[v];
	}
	ckmax(ans,s);
	f1[u]=ans;
}

void dfs2(int u=1, int p=0){
	int ans=gen[u];
	int s=-gen[u];
	for(auto v: adj[u]) if(v!=p){
		dfs2(v,u);
		ckmax(ans,f2[v]);
		s+=f1[v];

		if(gen[u]) ckmax(ans,f1[v]+1);
	}
	ckmax(ans,s);
	f2[u]=ans;
}

int main() {
    boost; IO();

    cin>>N; 
    FOR(i,0,N-1){
    	int u,v; cin>>u>>v;
    	adj[u].pb(v);
    	adj[v].pb(u);
    }
    FOR(i,1,N+1){
    	char c; cin>>c;
    	gen[i]=c-'0';
    }

    dfs1();
    dfs2();

    cout << f2[1] << endl;

    

    return 0;
}
//Change your approach 

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