Submission #959140

#	Time	Username	Problem	Language	Result	Execution time	Memory
959140		Pring	Power Plant (JOI20_power)	C++17	100 / 100	583 ms	26108 KiB

power

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

#ifdef MIKU
string dbmc = "\033[1;38;2;57;197;187m", dbrs = "\033[0m";
#define debug(x...) cout << dbmc << "[" << #x << "]: ", dout(x)
void dout() { cout << dbrs << endl; }
template <typename T, typename ...U>
void dout(T t, U ...u) { cout << t << (sizeof...(u) ? ", " : ""); dout(u...); }
#else
#define debug(...) 39
#endif

#define fs first
#define sc second
#define mp make_pair
#define FOR(i, j, k) for (int i = j, Z = k; i < Z; i++)
typedef pair<int, int> pii;

const int MXN = 200005;
int n;
vector<int> edge[MXN];
string s;
int sz[MXN], ans;
bitset<MXN> ban;

void GET_SZ(int id, int par) {
	sz[id] = 1;
	for (auto &i : edge[id]) {
		if (i == par) continue;
		if (ban[i]) continue;
		GET_SZ(i, id);
		sz[id] += sz[i];
	}
}

int GET_CD(int id, int par, int S) {
	for (auto &i : edge[id]) {
		if (i == par) continue;
		if (ban[i]) continue;
		if (sz[i] > S / 2) return GET_CD(i, id, S);
	}
	return id;
}

int DP(int id, int par) {
	int ans = ((s[id] & 1) ? -1 : 0);
	for (auto &i : edge[id]) {
		if (i == par) continue;
		if (ban[i]) continue;
		ans += DP(i, id);
	}
	if (s[id] & 1) ans = max(ans, 1);
	return ans;
}

int calc(int id) {
	int now = 0, cnt = 0, big = 0;
	for (auto &i : edge[id]) {
		if (ban[i]) continue;
		int x = DP(i, id);
		now += x;
		big = max(big, x);
		if (x) cnt++;
	}
	if (cnt == 0) return (s[id] & 1);
	if (cnt == 1) return now + (s[id] & 1);
	if (s[id] & 1) return max(1 + big, now - 1);
	return now;
}

void CD(int id) {
	GET_SZ(id, 0);
	int ct = GET_CD(id, 0, sz[id]);
	ans = max(ans, calc(ct));
	ban[ct] = true;
	for (auto &i : edge[ct]) {
		if (ban[i]) continue;
		CD(i);
	}
}

void miku() {
	int x, y;
	cin >> n;
	FOR(i, 1, n) {
		cin >> x >> y;
		edge[x].push_back(y);
		edge[y].push_back(x);
	}
	cin >> s;
	s = " " + s;
	CD(1);
	cout << ans << '\n';
}

int32_t main() {
	cin.tie(0) -> sync_with_stdio(false);
	cin.exceptions(cin.failbit);
	miku();
	return 0;
}

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