Submission #320770

#	Time	Username	Problem	Language	Result	Execution time	Memory
320770		gustason	Network (BOI15_net)	C++14	0 / 100	1 ms	364 KiB

net

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    cin >> n;
    vector<int> ind(n+1, 0), conn(n+1);
    for(int i = 0; i < n-1; i++) {
        int a, b;
        cin >> a >> b;
        ind[a]++;
        ind[b]++;
        conn[a] = b;
        conn[b] = a;
    }

    vector<int> edges;
    for(int i = 0; i <= n; i++) {
        if (ind[i] == 1) {
            edges.push_back(i);
        }
    }

    int sz = edges.size();
    cout << ceil((double) sz / 2) << "\n";
    for(int i = 2; i <= sz; i += 2) {
        cout << edges[i-1] << " " << edges[i-2] << "\n";
    }
    if (sz % 2) {
        int last = edges[sz-1];
        if (conn[last] == 1) {
            conn[last] = 2;
        } else {
            conn[last] = 1;
        }
        cout << last << " " << conn[last] << "\n";
    }
//    for(int i )
//    for(int i : edges) {
//        cout << i << " ";
//    }
    return 0;
}
//~ check for overflows

• Subtask 1: 0 / 18
• Subtask 2: 0 / 45
• Subtask 3: 0 / 37