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Submission #716069

# Submission time Handle Problem Language Result Execution time Memory
716069 2023-03-28T22:02:50 Z Charizard2021 Network (BOI15_net) C++17
100 / 100
 569 ms 93104 KB 
#include<bits/stdc++.h>
using namespace std;
const int N = 500001;
#define IOS ios::sync_with_stdio(false);; cin.tie(NULL)
bool visited[N];
int LeavesInsubtee[N];
vector<int> adj[N];
vector<int> res[N];
int n;
int ans = 0;
int cur_ans = 0;
int subtreeValue = 0;
void dfs(int u){
    visited[u] = true;
    if((int)adj[u].size() == 1){
        LeavesInsubtee[u] = 1;
    }
    for(int v : adj[u]){
        if(!visited[v]){
            dfs(v);
            LeavesInsubtee[u] += LeavesInsubtee[v];
        }
    }
}
void dfs2(int u){
    visited[u] = true;
    if((int)adj[u].size() == 1){
        res[subtreeValue].push_back(u);
    }
    for(int v : adj[u]){
        if(!visited[v]){
            dfs2(v);
        }
    }
}
int cutlocation(int u){
    visited[u] = true;
    for(int v : adj[u]){
        if(!visited[v]){
            if(LeavesInsubtee[v] > floor((cur_ans)/2)){
                return cutlocation(v);
            }
        }
    }
    return u;
}
int cut(int u){
    dfs(1);
    for(int i = 1; i <= n; i++){
        visited[i] = false;
    }
    int x = cutlocation(1);
    for(int i = 1; i <= n; i++){
        visited[i] = false;
    }
    visited[x] = true;
    for(int v : adj[x]){
        subtreeValue++;
        dfs2(v);
    }
    return x;
}
struct cmp{
    bool operator()(const int &a, const int &b) const{
        if(res[a].size() == res[b].size()){
            return a < b;
        }
        return res[a].size() > res[b].size();
    }
};
int main(){
    IOS;
    cin >> n;
    for(int i = 0; i < n - 1; i++){
        int a, b;
        cin >> a >> b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    for(int i = 1; i <= n; i++){
        if((int)adj[i].size() == 1){
            ans++;
        }
    }
    cur_ans = ans;
    ans = (ans + 1)/2;
    cout << ans << "\n";
    cut(n);
    vector<int> v;
    set<int, cmp> s;
    for(int i = 1; i <= subtreeValue; i++){
        s.insert(i);
    }
    while(!s.empty()){
        int a = *(s.begin());
        s.erase(a);
        v.push_back(res[a].back());
        res[a].pop_back();
        if(!s.empty()){
            int b = *(s.begin());
            s.erase(b);
            v.push_back(res[b].back());
            res[b].pop_back();
            if(!res[b].empty()){
                s.insert(b);
            }
        }
        if(!res[a].empty()){
            s.insert(a);
        }
    }
    if(v.size() % 2 == 1){
        v.push_back(res[1][0]);
    }
    for(int i = 0; i < (int)v.size(); i += 2){
        cout << v[i] << " " << v[i + 1] << "\n";
    }
}

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 23764 KB Output is correct
2 Correct 12 ms 23764 KB Output is correct
3 Correct 12 ms 23708 KB Output is correct
4 Correct 12 ms 23808 KB Output is correct
5 Correct 12 ms 23764 KB Output is correct
6 Correct 12 ms 23772 KB Output is correct
7 Correct 12 ms 23764 KB Output is correct
8 Correct 12 ms 23780 KB Output is correct
9 Correct 13 ms 23812 KB Output is correct
10 Correct 13 ms 23820 KB Output is correct
11 Correct 13 ms 23764 KB Output is correct
12 Correct 13 ms 23716 KB Output is correct
13 Correct 12 ms 23764 KB Output is correct
14 Correct 12 ms 23800 KB Output is correct
15 Correct 12 ms 23772 KB Output is correct
16 Correct 14 ms 23812 KB Output is correct
17 Correct 12 ms 23812 KB Output is correct
18 Correct 12 ms 23764 KB Output is correct
19 Correct 13 ms 23740 KB Output is correct
20 Correct 12 ms 23764 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 23764 KB Output is correct
2 Correct 12 ms 23764 KB Output is correct
3 Correct 12 ms 23708 KB Output is correct
4 Correct 12 ms 23808 KB Output is correct
5 Correct 12 ms 23764 KB Output is correct
6 Correct 12 ms 23772 KB Output is correct
7 Correct 12 ms 23764 KB Output is correct
8 Correct 12 ms 23780 KB Output is correct
9 Correct 13 ms 23812 KB Output is correct
10 Correct 13 ms 23820 KB Output is correct
11 Correct 13 ms 23764 KB Output is correct
12 Correct 13 ms 23716 KB Output is correct
13 Correct 12 ms 23764 KB Output is correct
14 Correct 12 ms 23800 KB Output is correct
15 Correct 12 ms 23772 KB Output is correct
16 Correct 14 ms 23812 KB Output is correct
17 Correct 12 ms 23812 KB Output is correct
18 Correct 12 ms 23764 KB Output is correct
19 Correct 13 ms 23740 KB Output is correct
20 Correct 12 ms 23764 KB Output is correct
21 Correct 13 ms 23816 KB Output is correct
22 Correct 14 ms 23892 KB Output is correct
23 Correct 13 ms 23952 KB Output is correct
24 Correct 14 ms 24020 KB Output is correct
25 Correct 14 ms 23912 KB Output is correct
26 Correct 13 ms 23896 KB Output is correct
27 Correct 13 ms 23868 KB Output is correct
28 Correct 13 ms 23824 KB Output is correct
29 Correct 13 ms 23892 KB Output is correct
30 Correct 13 ms 23764 KB Output is correct
31 Correct 13 ms 23868 KB Output is correct
32 Correct 13 ms 23700 KB Output is correct
33 Correct 14 ms 23764 KB Output is correct
34 Correct 13 ms 23764 KB Output is correct
35 Correct 12 ms 23764 KB Output is correct
36 Correct 14 ms 23812 KB Output is correct
37 Correct 12 ms 23784 KB Output is correct
38 Correct 12 ms 23812 KB Output is correct
39 Correct 14 ms 23820 KB Output is correct
40 Correct 13 ms 23780 KB Output is correct
41 Correct 13 ms 23808 KB Output is correct
42 Correct 13 ms 23812 KB Output is correct
43 Correct 15 ms 23892 KB Output is correct
44 Correct 13 ms 23736 KB Output is correct
45 Correct 13 ms 23808 KB Output is correct
46 Correct 13 ms 23764 KB Output is correct
47 Correct 14 ms 23764 KB Output is correct
48 Correct 13 ms 23728 KB Output is correct
49 Correct 13 ms 23892 KB Output is correct
50 Correct 13 ms 23768 KB Output is correct
51 Correct 12 ms 23812 KB Output is correct
52 Correct 13 ms 23736 KB Output is correct
53 Correct 13 ms 23768 KB Output is correct
54 Correct 13 ms 23768 KB Output is correct
55 Correct 13 ms 23812 KB Output is correct
56 Correct 12 ms 23764 KB Output is correct
57 Correct 12 ms 23764 KB Output is correct
58 Correct 14 ms 23952 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 23764 KB Output is correct
2 Correct 12 ms 23764 KB Output is correct
3 Correct 12 ms 23708 KB Output is correct
4 Correct 12 ms 23808 KB Output is correct
5 Correct 12 ms 23764 KB Output is correct
6 Correct 12 ms 23772 KB Output is correct
7 Correct 12 ms 23764 KB Output is correct
8 Correct 12 ms 23780 KB Output is correct
9 Correct 13 ms 23812 KB Output is correct
10 Correct 13 ms 23820 KB Output is correct
11 Correct 13 ms 23764 KB Output is correct
12 Correct 13 ms 23716 KB Output is correct
13 Correct 12 ms 23764 KB Output is correct
14 Correct 12 ms 23800 KB Output is correct
15 Correct 12 ms 23772 KB Output is correct
16 Correct 14 ms 23812 KB Output is correct
17 Correct 12 ms 23812 KB Output is correct
18 Correct 12 ms 23764 KB Output is correct
19 Correct 13 ms 23740 KB Output is correct
20 Correct 12 ms 23764 KB Output is correct
21 Correct 13 ms 23816 KB Output is correct
22 Correct 14 ms 23892 KB Output is correct
23 Correct 13 ms 23952 KB Output is correct
24 Correct 14 ms 24020 KB Output is correct
25 Correct 14 ms 23912 KB Output is correct
26 Correct 13 ms 23896 KB Output is correct
27 Correct 13 ms 23868 KB Output is correct
28 Correct 13 ms 23824 KB Output is correct
29 Correct 13 ms 23892 KB Output is correct
30 Correct 13 ms 23764 KB Output is correct
31 Correct 13 ms 23868 KB Output is correct
32 Correct 13 ms 23700 KB Output is correct
33 Correct 14 ms 23764 KB Output is correct
34 Correct 13 ms 23764 KB Output is correct
35 Correct 12 ms 23764 KB Output is correct
36 Correct 14 ms 23812 KB Output is correct
37 Correct 12 ms 23784 KB Output is correct
38 Correct 12 ms 23812 KB Output is correct
39 Correct 14 ms 23820 KB Output is correct
40 Correct 13 ms 23780 KB Output is correct
41 Correct 13 ms 23808 KB Output is correct
42 Correct 13 ms 23812 KB Output is correct
43 Correct 15 ms 23892 KB Output is correct
44 Correct 13 ms 23736 KB Output is correct
45 Correct 13 ms 23808 KB Output is correct
46 Correct 13 ms 23764 KB Output is correct
47 Correct 14 ms 23764 KB Output is correct
48 Correct 13 ms 23728 KB Output is correct
49 Correct 13 ms 23892 KB Output is correct
50 Correct 13 ms 23768 KB Output is correct
51 Correct 12 ms 23812 KB Output is correct
52 Correct 13 ms 23736 KB Output is correct
53 Correct 13 ms 23768 KB Output is correct
54 Correct 13 ms 23768 KB Output is correct
55 Correct 13 ms 23812 KB Output is correct
56 Correct 12 ms 23764 KB Output is correct
57 Correct 12 ms 23764 KB Output is correct
58 Correct 14 ms 23952 KB Output is correct
59 Correct 521 ms 55536 KB Output is correct
60 Correct 492 ms 49048 KB Output is correct
61 Correct 12 ms 23816 KB Output is correct
62 Correct 13 ms 23760 KB Output is correct
63 Correct 437 ms 53924 KB Output is correct
64 Correct 14 ms 24332 KB Output is correct
65 Correct 24 ms 26076 KB Output is correct
66 Correct 163 ms 43064 KB Output is correct
67 Correct 539 ms 65228 KB Output is correct
68 Correct 558 ms 66248 KB Output is correct
69 Correct 24 ms 25748 KB Output is correct
70 Correct 146 ms 44064 KB Output is correct
71 Correct 569 ms 93104 KB Output is correct
72 Correct 496 ms 88036 KB Output is correct
73 Correct 111 ms 31752 KB Output is correct
74 Correct 487 ms 52876 KB Output is correct
75 Correct 44 ms 29004 KB Output is correct
76 Correct 435 ms 73648 KB Output is correct
77 Correct 472 ms 74292 KB Output is correct
78 Correct 35 ms 27596 KB Output is correct
79 Correct 553 ms 62960 KB Output is correct
80 Correct 15 ms 24148 KB Output is correct
81 Correct 153 ms 39948 KB Output is correct
82 Correct 550 ms 72304 KB Output is correct
83 Correct 467 ms 52948 KB Output is correct
84 Correct 453 ms 53412 KB Output is correct
85 Correct 497 ms 53300 KB Output is correct
86 Correct 486 ms 55176 KB Output is correct
87 Correct 453 ms 55200 KB Output is correct