Submission #1127369

#	Time	Username	Problem	Language	Result	Execution time	Memory
1127369		Peter2017	Power Plant (JOI20_power)	C++20	100 / 100	121 ms	26104 KiB

power

#include <bits/stdc++.h>
#define fi first
#define se second
#define ll long long
#define pii pair<int,int>
#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)
#define mem(a, b) memset(a, b, sizeof(a))
#define name "test"

using namespace std;

const int N = 2e5 + 5;
const int mod = 1e9 + 7;

template <typename T1, typename T2> bool maxi(T1 &a, T2 b){if (a < b){a = b; return 1;} return 0;}
template <typename T1, typename T2> bool mini(T1 &a, T2 b){if (a > b){a = b; return 1;} return 0;}

int n;
int ans;
int f[N];
string s;
vector<int> adj[N];

void load(){
	cin.tie(0)->sync_with_stdio(0);
	if (fopen(name".inp", "r")){
		freopen(name".inp", "r", stdin);
		freopen(name".out", "w", stdout);
	}
}

void input(){
	cin >> n;
	for (int i = 1; i < n; i++){
		int u, v; cin >> u >> v;
		adj[u].push_back(v);
		adj[v].push_back(u);
	}
	cin >> s;
	s = " " + s;
}

void dfs(int u, int pre){
	int sum = 0;
	int x = (s[u] == '1');
	f[u] = x;
	for (int v : adj[u]) if (v != pre){
		dfs(v, u);
		maxi(ans, f[v] + x);
		sum += f[v];
	}
	maxi(f[u], sum - x);
	maxi(ans, f[u]);
}

void solve(){
	dfs(1, 0);
	cout << ans;
}

int main(){
	load();
	input();
	solve();
}

Compilation message (stderr)

power.cpp: In function 'void load()':
power.cpp:28:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   28 |                 freopen(name".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
power.cpp:29:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   29 |                 freopen(name".out", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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