Submission #561805

#	Time	Username	Problem	Language	Result	Execution time	Memory
561805		4fecta	Power Plant (JOI20_power)	C++17	6 / 100	44 ms	5292 KiB

power

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define int ll
#define ld long double
#define pii pair<int, int>
#define f first
#define s second
#define boost() cin.tie(0), cin.sync_with_stdio(0)

const int MN = 200005;

int n, u, v, p[MN], dp[MN], ans;
char c;
vector<int> a[MN];

void dfs(int cur, int par, int rt) {
    int sum = 0;
    for (int nxt : a[cur]) {
        if (nxt == par) continue;
        dfs(nxt, cur, rt);
        sum += dp[nxt];
    }
    if (p[cur] && cur == rt) {
        if (a[rt].size() == 1) dp[cur] = sum + 1;
        else dp[cur] = max(1ll, sum - 1);
    }
    else if (p[cur]) dp[cur] = max(1ll, sum - 1);
    else dp[cur] = sum;
}

bool cmp(int x, int y) {
    return a[x].size() > a[y].size();
}

int32_t main() {
    boost();

    cin >> n;
    for (int i = 1; i < n; i++) {
        cin >> u >> v;
        a[u].push_back(v);
        a[v].push_back(u);
    }
    for (int i = 1; i <= n; i++) cin >> c, p[i] = c - '0';
    vector<int> vec;
    for (int i = 1; i <= n; i++) vec.push_back(i);
    sort(vec.begin(), vec.end(), cmp);
    for (int i = 0; i < min(n, 1000ll); i++) {
        dfs(vec[i], 0, vec[i]);
        ans = max(ans, dp[vec[i]]);
    }
    printf("%lld\n", ans);

    return 0;
}

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