Submission #1052628

#	Time	Username	Problem	Language	Result	Execution time	Memory
1052628		turska	Railway (BOI17_railway)	C++17	100 / 100	116 ms	31244 KiB

railway

#include <bits/stdc++.h>
using namespace std;
 
int n, m, k, u, v, s, h;
#define P push_back
#define N 100001
vector<pair<int, int>> adj[N];
vector<int> q[N];
 
int z[N];
 
vector<int> A;
 
map<int, int> dfs(int v, int p) {
    map<int, int> a;
 
    for (auto [u, i]: adj[v]) if (u!=p) {
        map<int, int> b = dfs(u, v);
 
        if (b.size()>=k) {
            A.P(i);
        }
 
        if (a.size() < b.size()) a.swap(b);
        for (auto [k, v]: b) {
            if (a[k]+v==z[k]) a.erase(k);
            else a[k] += v;
        }
    }
 
    for (auto u: q[v]) {
        a[u]++;
        if (a[u] == z[u]) a.erase(u);
    }
    return a;
}
int main() {
    cin >> n >> m >> k;
 
    for (int i=0; i<n-1; i++) {
        cin >> u >> v;
        adj[u].P({v, i});
        adj[v].P({u, i});
    }
    for (int i=0; i<m; i++) {
        cin >> s;
        z[i] = s;
        for (int j=0; j<s; j++) {
            cin >> h;
            q[h].P(i);
        }
    }
    dfs(1, 1);
    sort(A.begin(), A.end());
    cout << A.size() << '\n';
    for (auto i: A) cout << i+1 << ' ';
}

Compilation message (stderr)

railway.cpp: In function 'std::map<int, int> dfs(int, int)':
railway.cpp:20:21: warning: comparison of integer expressions of different signedness: 'std::map<int, int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   20 |         if (b.size()>=k) {
      |             ~~~~~~~~^~~

• Subtask 1: 8 / 8
• Subtask 2: 15 / 15
• Subtask 3: 7 / 7
• Subtask 4: 29 / 29
• Subtask 5: 16 / 16
• Subtask 6: 25 / 25