Submission #1282636

#	Time	Username	Problem	Language	Result	Execution time	Memory
1282636		KickingKun	Power Plant (JOI20_power)	C++20	47 / 100	1595 ms	12612 KiB

power

#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define ull unsigned long long
#define ld long double
#define bigint __int128
#define emb emplace_back
#define pb push_back
#define pii pair <int, int>
#define fi first
#define se second
#define all(v) v.begin(), v.end()
#define Task ""

#define MASK(k) (1ull << k)
#define bitcnt(k) __builtin_popcount(k)
#define testBit(n, k) ((n >> k) & 1)
#define flipBit(n, k) (n ^ (1ll << k))
#define offBit(n, k) (n & ~MASK(k))
#define onBit(n, k) (n | (1ll << k))

template <class T> bool minimize(T &a, T b) {if (a > b) {a = b; return true;} return false;}
template <class T> bool maximize(T &a, T b) {if (a < b) {a = b; return true;} return false;}

const int N = 2e5 + 5, lim = 60, mod = 1e9 + 7;
const ll INF = 1e18;

int n, dp[N];
vector <int> adj[N];
string s;

void dfs(int u, int p = -1) {
	dp[u] = 0; int sum = 0, cnt = 0;
	for (int v: adj[u]) if (v != p) {
		dfs(v, u);
		sum += dp[v];
		cnt += dp[v] > 0;
	}
	dp[u] = max(int(s[u] == '1'), sum - (s[u] == '1'));
}

int main() {
	ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);

	if (fopen(Task".inp", "r")) {
		freopen(Task".inp", "r", stdin);
		freopen(Task".out", "w", stdout);
	}

	cin >> n;
	for (int i = 1; i < n; i++) {
		int u, v; cin >> u >> v;
		adj[u].emb(v); adj[v].emb(u);
	}
	cin >> s; s = '#' + s;

	int ans = 0;
	for (int u = 1; u <= n; u++) if (s[u] == '1') {
		dfs(u); maximize(ans, dp[u]);
		for (int v: adj[u]) maximize(ans, dp[v] + (s[u] == '1'));
	}
	cout << ans;
}

Compilation message (stderr)

power.cpp: In function 'int main()':
power.cpp:47:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   47 |                 freopen(Task".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
power.cpp:48:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   48 |                 freopen(Task".out", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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