Submission #668143

#	Time	Username	Problem	Language	Result	Execution time	Memory
668143		stevancv	Power Plant (JOI20_power)	C++14	0 / 100	4 ms	5076 KiB

power

#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define sp ' '
#define en '\n'
#define smin(a, b) a = min(a, b)
#define smax(a, b) a = max(a, b)
using namespace std;
const int N = 2e5 + 2;
const int inf = 2e9;
vector<int> g[N];
int dp[N][2];
int str[N];
void Dfs(int s, int e) {
    dp[s][0] = -str[s];
    dp[s][1] = -inf;
    for (int u : g[s]) {
        if (u == e) continue;
        Dfs(u, s);
        dp[s][0] += max(dp[u][0], dp[u][1] - 2);
        if (dp[u][1] >= 2) smax(dp[s][1], dp[u][1] - 2 * str[s]);
        if (str[s] == 1 && dp[u][0] >= 1) smax(dp[s][1], dp[u][0] + 1);
    }
    smax(dp[s][0], str[s]);
    //cout << s + 1 << " : " << dp[s][0] << sp << dp[s][1] << en;
}
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n; cin >> n;
    for (int i = 0; i < n - 1; i++) {
        int u, v;
        cin >> u >> v;
        u -= 1;
        v -= 1;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    string sr;
    cin >> sr;
    for (int i = 0; i < n; i++) str[i] = sr[i] - '0';
    Dfs(0, -1);
    cout << max(dp[0][0], dp[0][1]) << en;
    return 0;
}

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