Submission #1052630

#	Time	Username	Problem	Language	Result	Execution time	Memory
1052630		turska	Railway (BOI17_railway)	C++17	100 / 100	137 ms	31176 KiB

railway

#include <bits/stdc++.h>
using namespace std;
#define P push_back
#define N 100001
#define I int
I n, m, k, u, v, s, h;
vector<pair<I, I>> adj[N];
vector<I> q[N];
I z[N];
vector<I> A;
map<I, I> G(I v, I p) {
    map<I, I> a;
    for (auto [u, i]: adj[v]) if (u!=p) {
        map<I, I> b = G(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;
}
I main() {
    cin >> n >> m >> k;
    for (I i=0; i<n-1; i++) {
        cin >> u >> v;
        adj[u].P({v, i});
        adj[v].P({u, i});
    }
    for (I i=0; i<m; i++) {
        cin >> s;
        z[i] = s;
        for (I j=0; j<s; j++) {
            cin >> h;
            q[h].P(i);
        }
    }
    G(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> G(int, int)':
railway.cpp:15:21: warning: comparison of integer expressions of different signedness: 'std::map<int, int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   15 |         if (b.size()>=k)  A.P(i);
      |             ~~~~~~~~^~~

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