Submission #911141

# Submission time Handle Problem Language Result Execution time Memory
911141 2024-01-18T13:33:12 Z ttamx Network (BOI15_net) C++14
100 / 100
639 ms 70808 KB
#include<bits/stdc++.h>

using namespace std;

const int N=5e5+5;

int n;
int 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;
    int cnt=0;
    for(auto v:adj[c]){
        res.push_back({});
        dfs(v,c,res.back());
    }
    int m=res.size();
    priority_queue<pair<int,int>> pq;
    for(int i=0;i<m;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() << "\n";
    for(auto [x,y]:ans)cout << x << " " << y << "\n";
}

Compilation message

net.cpp: In function 'int main()':
net.cpp:48:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   48 |         auto [s,i]=pq.top();
      |              ^
net.cpp:54:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   54 |         auto [t,j]=pq.top();
      |              ^
net.cpp:63:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   63 |     for(auto [x,y]:ans)cout << x << " " << y << "\n";
      |              ^
net.cpp:38:9: warning: unused variable 'cnt' [-Wunused-variable]
   38 |     int cnt=0;
      |         ^~~
# Verdict Execution time Memory Grader output
1 Correct 3 ms 12888 KB Output is correct
2 Correct 3 ms 12892 KB Output is correct
3 Correct 3 ms 12892 KB Output is correct
4 Correct 4 ms 12888 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 12896 KB Output is correct
8 Correct 3 ms 12888 KB Output is correct
9 Correct 3 ms 12916 KB Output is correct
10 Correct 3 ms 13144 KB Output is correct
11 Correct 4 ms 12892 KB Output is correct
12 Correct 4 ms 12892 KB Output is correct
13 Correct 4 ms 12892 KB Output is correct
14 Correct 4 ms 12892 KB Output is correct
15 Correct 3 ms 12892 KB Output is correct
16 Correct 4 ms 13144 KB Output is correct
17 Correct 3 ms 12892 KB Output is correct
18 Correct 3 ms 12892 KB Output is correct
19 Correct 3 ms 12892 KB Output is correct
20 Correct 3 ms 12892 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 3 ms 12888 KB Output is correct
2 Correct 3 ms 12892 KB Output is correct
3 Correct 3 ms 12892 KB Output is correct
4 Correct 4 ms 12888 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 12896 KB Output is correct
8 Correct 3 ms 12888 KB Output is correct
9 Correct 3 ms 12916 KB Output is correct
10 Correct 3 ms 13144 KB Output is correct
11 Correct 4 ms 12892 KB Output is correct
12 Correct 4 ms 12892 KB Output is correct
13 Correct 4 ms 12892 KB Output is correct
14 Correct 4 ms 12892 KB Output is correct
15 Correct 3 ms 12892 KB Output is correct
16 Correct 4 ms 13144 KB Output is correct
17 Correct 3 ms 12892 KB Output is correct
18 Correct 3 ms 12892 KB Output is correct
19 Correct 3 ms 12892 KB Output is correct
20 Correct 3 ms 12892 KB Output is correct
21 Correct 3 ms 12892 KB Output is correct
22 Correct 4 ms 12892 KB Output is correct
23 Correct 5 ms 12892 KB Output is correct
24 Correct 5 ms 13144 KB Output is correct
25 Correct 4 ms 12888 KB Output is correct
26 Correct 3 ms 12892 KB Output is correct
27 Correct 4 ms 12892 KB Output is correct
28 Correct 5 ms 12892 KB Output is correct
29 Correct 4 ms 12892 KB Output is correct
30 Correct 3 ms 12892 KB Output is correct
31 Correct 5 ms 13144 KB Output is correct
32 Correct 4 ms 12892 KB Output is correct
33 Correct 4 ms 12892 KB Output is correct
34 Correct 3 ms 12892 KB Output is correct
35 Correct 3 ms 12940 KB Output is correct
36 Correct 3 ms 12892 KB Output is correct
37 Correct 4 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 4 ms 12892 KB Output is correct
41 Correct 3 ms 12892 KB Output is correct
42 Correct 4 ms 12888 KB Output is correct
43 Correct 4 ms 12892 KB Output is correct
44 Correct 3 ms 12892 KB Output is correct
45 Correct 3 ms 12892 KB Output is correct
46 Correct 3 ms 12892 KB Output is correct
47 Correct 3 ms 12892 KB Output is correct
48 Correct 3 ms 12892 KB Output is correct
49 Correct 3 ms 12892 KB Output is correct
50 Correct 4 ms 12908 KB Output is correct
51 Correct 3 ms 12892 KB Output is correct
52 Correct 4 ms 13144 KB Output is correct
53 Correct 4 ms 12888 KB Output is correct
54 Correct 3 ms 12892 KB Output is correct
55 Correct 4 ms 12892 KB Output is correct
56 Correct 3 ms 12892 KB Output is correct
57 Correct 4 ms 12892 KB Output is correct
58 Correct 4 ms 12892 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 3 ms 12888 KB Output is correct
2 Correct 3 ms 12892 KB Output is correct
3 Correct 3 ms 12892 KB Output is correct
4 Correct 4 ms 12888 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 12896 KB Output is correct
8 Correct 3 ms 12888 KB Output is correct
9 Correct 3 ms 12916 KB Output is correct
10 Correct 3 ms 13144 KB Output is correct
11 Correct 4 ms 12892 KB Output is correct
12 Correct 4 ms 12892 KB Output is correct
13 Correct 4 ms 12892 KB Output is correct
14 Correct 4 ms 12892 KB Output is correct
15 Correct 3 ms 12892 KB Output is correct
16 Correct 4 ms 13144 KB Output is correct
17 Correct 3 ms 12892 KB Output is correct
18 Correct 3 ms 12892 KB Output is correct
19 Correct 3 ms 12892 KB Output is correct
20 Correct 3 ms 12892 KB Output is correct
21 Correct 3 ms 12892 KB Output is correct
22 Correct 4 ms 12892 KB Output is correct
23 Correct 5 ms 12892 KB Output is correct
24 Correct 5 ms 13144 KB Output is correct
25 Correct 4 ms 12888 KB Output is correct
26 Correct 3 ms 12892 KB Output is correct
27 Correct 4 ms 12892 KB Output is correct
28 Correct 5 ms 12892 KB Output is correct
29 Correct 4 ms 12892 KB Output is correct
30 Correct 3 ms 12892 KB Output is correct
31 Correct 5 ms 13144 KB Output is correct
32 Correct 4 ms 12892 KB Output is correct
33 Correct 4 ms 12892 KB Output is correct
34 Correct 3 ms 12892 KB Output is correct
35 Correct 3 ms 12940 KB Output is correct
36 Correct 3 ms 12892 KB Output is correct
37 Correct 4 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 4 ms 12892 KB Output is correct
41 Correct 3 ms 12892 KB Output is correct
42 Correct 4 ms 12888 KB Output is correct
43 Correct 4 ms 12892 KB Output is correct
44 Correct 3 ms 12892 KB Output is correct
45 Correct 3 ms 12892 KB Output is correct
46 Correct 3 ms 12892 KB Output is correct
47 Correct 3 ms 12892 KB Output is correct
48 Correct 3 ms 12892 KB Output is correct
49 Correct 3 ms 12892 KB Output is correct
50 Correct 4 ms 12908 KB Output is correct
51 Correct 3 ms 12892 KB Output is correct
52 Correct 4 ms 13144 KB Output is correct
53 Correct 4 ms 12888 KB Output is correct
54 Correct 3 ms 12892 KB Output is correct
55 Correct 4 ms 12892 KB Output is correct
56 Correct 3 ms 12892 KB Output is correct
57 Correct 4 ms 12892 KB Output is correct
58 Correct 4 ms 12892 KB Output is correct
59 Correct 414 ms 44320 KB Output is correct
60 Correct 412 ms 36040 KB Output is correct
61 Correct 3 ms 12892 KB Output is correct
62 Correct 3 ms 12892 KB Output is correct
63 Correct 318 ms 38068 KB Output is correct
64 Correct 5 ms 13404 KB Output is correct
65 Correct 12 ms 14684 KB Output is correct
66 Correct 154 ms 29032 KB Output is correct
67 Correct 639 ms 46588 KB Output is correct
68 Correct 596 ms 47596 KB Output is correct
69 Correct 10 ms 14596 KB Output is correct
70 Correct 78 ms 30396 KB Output is correct
71 Correct 354 ms 70808 KB Output is correct
72 Correct 349 ms 66732 KB Output is correct
73 Correct 55 ms 18380 KB Output is correct
74 Correct 445 ms 34064 KB Output is correct
75 Correct 25 ms 17172 KB Output is correct
76 Correct 373 ms 54716 KB Output is correct
77 Correct 326 ms 55856 KB Output is correct
78 Correct 21 ms 15696 KB Output is correct
79 Correct 616 ms 44244 KB Output is correct
80 Correct 6 ms 13168 KB Output is correct
81 Correct 82 ms 25724 KB Output is correct
82 Correct 397 ms 53468 KB Output is correct
83 Correct 483 ms 34368 KB Output is correct
84 Correct 492 ms 34500 KB Output is correct
85 Correct 415 ms 34576 KB Output is correct
86 Correct 451 ms 36556 KB Output is correct
87 Correct 447 ms 36444 KB Output is correct