Submission #940078

# Submission time Handle Problem Language Result Execution time Memory
940078 2024-03-07T05:11:57 Z vjudge1 Network (BOI15_net) C++17
100 / 100
671 ms 70480 KB
#include<bits/stdc++.h>
using namespace std;

const int N = 5e5 + 10;

int n, sz[N];
vector<int> adj[N];

int dfssz(int u, int p = 0){
    sz[u] = (adj[u].size() < 2);
    for (auto v : adj[u])
        if (v ^ p) sz[u] += dfssz(v, u);
    return sz[u];
}
 
int centroid(int u, int cnt, int p = 0){
    for (auto v : adj[u])
        if(v ^ p && sz[v] > cnt / 2) return centroid(v, cnt, u);
    return u;
}
 
void dfs(int u, int p, vector<int> &comp){
    if (adj[u].size() == 1) comp.emplace_back(u);
    for (auto v : adj[u])
        if(v ^ p) dfs(v,u,comp);
}
 
int main(){
    cin.tie(nullptr)->sync_with_stdio(false);
    cin >> n;
    for (int i = 1; i < n; i++) {
        int u,v;
        cin >> u >> v;
        adj[u].emplace_back(v);
        adj[v].emplace_back(u);
    }
    int c = centroid(1, dfssz(1));
    vector<vector<int>> res;
    for(auto v:adj[c]) {
        res.push_back({});
        dfs(v,c,res.back());
    }
    priority_queue<pair<int,int>> pq;
    for (int i = 0; i < res.size(); i++) pq.emplace(res[i].size(),i);
    vector<pair<int,int>> ans;
    while (!pq.empty()) {
        auto [s,i]=pq.top();
        pq.pop();
        if (pq.empty()){
            ans.emplace_back(res[i].back(),c);
            break;
        }
        auto [t,j] = pq.top();
        pq.pop();
        ans.emplace_back(res[i].back(),res[j].back());
        res[i].pop_back();
        res[j].pop_back();
        if(--s) pq.emplace(s,i);
        if(--t) pq.emplace(t,j);
    }
    cout << ans.size() << endl;
    for(auto [x,y] : ans) cout << x << " " << y << endl;
}

Compilation message

net.cpp: In function 'int main()':
net.cpp:44:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   44 |     for (int i = 0; i < res.size(); i++) pq.emplace(res[i].size(),i);
      |                     ~~^~~~~~~~~~~~
# Verdict Execution time Memory Grader output
1 Correct 3 ms 12888 KB Output is correct
2 Correct 4 ms 13144 KB Output is correct
3 Correct 3 ms 12892 KB Output is correct
4 Correct 4 ms 12892 KB Output is correct
5 Correct 4 ms 12892 KB Output is correct
6 Correct 3 ms 12892 KB Output is correct
7 Correct 3 ms 12892 KB Output is correct
8 Correct 3 ms 12888 KB Output is correct
9 Correct 3 ms 12892 KB Output is correct
10 Correct 4 ms 13144 KB Output is correct
11 Correct 3 ms 12892 KB Output is correct
12 Correct 3 ms 12892 KB Output is correct
13 Correct 3 ms 12952 KB Output is correct
14 Correct 3 ms 12892 KB Output is correct
15 Correct 3 ms 12892 KB Output is correct
16 Correct 5 ms 12912 KB Output is correct
17 Correct 3 ms 12896 KB Output is correct
18 Correct 3 ms 12888 KB Output is correct
19 Correct 4 ms 12912 KB Output is correct
20 Correct 3 ms 12896 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 3 ms 12888 KB Output is correct
2 Correct 4 ms 13144 KB Output is correct
3 Correct 3 ms 12892 KB Output is correct
4 Correct 4 ms 12892 KB Output is correct
5 Correct 4 ms 12892 KB Output is correct
6 Correct 3 ms 12892 KB Output is correct
7 Correct 3 ms 12892 KB Output is correct
8 Correct 3 ms 12888 KB Output is correct
9 Correct 3 ms 12892 KB Output is correct
10 Correct 4 ms 13144 KB Output is correct
11 Correct 3 ms 12892 KB Output is correct
12 Correct 3 ms 12892 KB Output is correct
13 Correct 3 ms 12952 KB Output is correct
14 Correct 3 ms 12892 KB Output is correct
15 Correct 3 ms 12892 KB Output is correct
16 Correct 5 ms 12912 KB Output is correct
17 Correct 3 ms 12896 KB Output is correct
18 Correct 3 ms 12888 KB Output is correct
19 Correct 4 ms 12912 KB Output is correct
20 Correct 3 ms 12896 KB Output is correct
21 Correct 3 ms 12896 KB Output is correct
22 Correct 5 ms 12892 KB Output is correct
23 Correct 5 ms 13120 KB Output is correct
24 Correct 5 ms 13148 KB Output is correct
25 Correct 4 ms 12896 KB Output is correct
26 Correct 4 ms 12892 KB Output is correct
27 Correct 4 ms 12896 KB Output is correct
28 Correct 5 ms 12892 KB Output is correct
29 Correct 4 ms 12904 KB Output is correct
30 Correct 3 ms 12892 KB Output is correct
31 Correct 4 ms 12892 KB Output is correct
32 Correct 3 ms 12892 KB Output is correct
33 Correct 4 ms 12892 KB Output is correct
34 Correct 3 ms 12888 KB Output is correct
35 Correct 3 ms 12892 KB Output is correct
36 Correct 3 ms 12892 KB Output is correct
37 Correct 3 ms 12892 KB Output is correct
38 Correct 3 ms 12892 KB Output is correct
39 Correct 3 ms 12892 KB Output is correct
40 Correct 3 ms 12892 KB Output is correct
41 Correct 4 ms 12892 KB Output is correct
42 Correct 3 ms 12892 KB Output is correct
43 Correct 4 ms 12892 KB Output is correct
44 Correct 3 ms 12892 KB Output is correct
45 Correct 4 ms 12892 KB Output is correct
46 Correct 4 ms 12892 KB Output is correct
47 Correct 3 ms 12892 KB Output is correct
48 Correct 3 ms 12888 KB Output is correct
49 Correct 3 ms 12916 KB Output is correct
50 Correct 3 ms 12888 KB Output is correct
51 Correct 4 ms 13144 KB Output is correct
52 Correct 3 ms 12892 KB Output is correct
53 Correct 4 ms 12892 KB Output is correct
54 Correct 4 ms 12892 KB Output is correct
55 Correct 3 ms 12892 KB Output is correct
56 Correct 3 ms 12888 KB Output is correct
57 Correct 3 ms 12892 KB Output is correct
58 Correct 5 ms 12892 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 3 ms 12888 KB Output is correct
2 Correct 4 ms 13144 KB Output is correct
3 Correct 3 ms 12892 KB Output is correct
4 Correct 4 ms 12892 KB Output is correct
5 Correct 4 ms 12892 KB Output is correct
6 Correct 3 ms 12892 KB Output is correct
7 Correct 3 ms 12892 KB Output is correct
8 Correct 3 ms 12888 KB Output is correct
9 Correct 3 ms 12892 KB Output is correct
10 Correct 4 ms 13144 KB Output is correct
11 Correct 3 ms 12892 KB Output is correct
12 Correct 3 ms 12892 KB Output is correct
13 Correct 3 ms 12952 KB Output is correct
14 Correct 3 ms 12892 KB Output is correct
15 Correct 3 ms 12892 KB Output is correct
16 Correct 5 ms 12912 KB Output is correct
17 Correct 3 ms 12896 KB Output is correct
18 Correct 3 ms 12888 KB Output is correct
19 Correct 4 ms 12912 KB Output is correct
20 Correct 3 ms 12896 KB Output is correct
21 Correct 3 ms 12896 KB Output is correct
22 Correct 5 ms 12892 KB Output is correct
23 Correct 5 ms 13120 KB Output is correct
24 Correct 5 ms 13148 KB Output is correct
25 Correct 4 ms 12896 KB Output is correct
26 Correct 4 ms 12892 KB Output is correct
27 Correct 4 ms 12896 KB Output is correct
28 Correct 5 ms 12892 KB Output is correct
29 Correct 4 ms 12904 KB Output is correct
30 Correct 3 ms 12892 KB Output is correct
31 Correct 4 ms 12892 KB Output is correct
32 Correct 3 ms 12892 KB Output is correct
33 Correct 4 ms 12892 KB Output is correct
34 Correct 3 ms 12888 KB Output is correct
35 Correct 3 ms 12892 KB Output is correct
36 Correct 3 ms 12892 KB Output is correct
37 Correct 3 ms 12892 KB Output is correct
38 Correct 3 ms 12892 KB Output is correct
39 Correct 3 ms 12892 KB Output is correct
40 Correct 3 ms 12892 KB Output is correct
41 Correct 4 ms 12892 KB Output is correct
42 Correct 3 ms 12892 KB Output is correct
43 Correct 4 ms 12892 KB Output is correct
44 Correct 3 ms 12892 KB Output is correct
45 Correct 4 ms 12892 KB Output is correct
46 Correct 4 ms 12892 KB Output is correct
47 Correct 3 ms 12892 KB Output is correct
48 Correct 3 ms 12888 KB Output is correct
49 Correct 3 ms 12916 KB Output is correct
50 Correct 3 ms 12888 KB Output is correct
51 Correct 4 ms 13144 KB Output is correct
52 Correct 3 ms 12892 KB Output is correct
53 Correct 4 ms 12892 KB Output is correct
54 Correct 4 ms 12892 KB Output is correct
55 Correct 3 ms 12892 KB Output is correct
56 Correct 3 ms 12888 KB Output is correct
57 Correct 3 ms 12892 KB Output is correct
58 Correct 5 ms 12892 KB Output is correct
59 Correct 517 ms 45304 KB Output is correct
60 Correct 541 ms 35884 KB Output is correct
61 Correct 3 ms 12892 KB Output is correct
62 Correct 3 ms 12892 KB Output is correct
63 Correct 491 ms 38252 KB Output is correct
64 Correct 4 ms 13400 KB Output is correct
65 Correct 12 ms 14684 KB Output is correct
66 Correct 139 ms 29084 KB Output is correct
67 Correct 487 ms 46564 KB Output is correct
68 Correct 493 ms 47496 KB Output is correct
69 Correct 17 ms 14484 KB Output is correct
70 Correct 179 ms 30216 KB Output is correct
71 Correct 581 ms 70480 KB Output is correct
72 Correct 604 ms 67344 KB Output is correct
73 Correct 115 ms 18424 KB Output is correct
74 Correct 557 ms 34436 KB Output is correct
75 Correct 53 ms 17364 KB Output is correct
76 Correct 596 ms 54660 KB Output is correct
77 Correct 671 ms 55948 KB Output is correct
78 Correct 39 ms 15932 KB Output is correct
79 Correct 563 ms 44236 KB Output is correct
80 Correct 7 ms 13148 KB Output is correct
81 Correct 215 ms 25788 KB Output is correct
82 Correct 626 ms 53056 KB Output is correct
83 Correct 519 ms 34044 KB Output is correct
84 Correct 572 ms 34628 KB Output is correct
85 Correct 600 ms 34492 KB Output is correct
86 Correct 578 ms 36476 KB Output is correct
87 Correct 518 ms 36696 KB Output is correct