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Submission #452114

# Submission time Handle Problem Language Result Execution time Memory
452114 2021-08-03T19:35:36 Z JovanB Network (BOI15_net) C++17
100 / 100
 624 ms 54232 KB 
#include <bits/stdc++.h>
using namespace std;
 
int ukup=0;
int leafs=0;
int leafs1=0;
vector <int> graf[500005];
bool visited[500005];
int listovi[500005];
int brlist[500005];
 
void dfs1(int v){
    visited[v] = 1;
    bool nes = 0;
    for(auto c : graf[v]){
        if(!visited[c]){dfs1(c); nes=1; brlist[v] += brlist[c];}
    }
    if(nes == 0) {leafs++; brlist[v] = 1;}
}
 
void dfs3(int v){
    visited[v] = 1;
    bool nes = 0;
    for(auto c : graf[v]){
        if(!visited[c]){dfs3(c); nes=1;}
    }
    if(nes == 0){leafs++; listovi[leafs] = v;}
}
 
int main(){
    ios_base::sync_with_stdio(false),cin.tie(0),cerr.tie(0),cout.tie(0);
    cout.precision(10);
    cout<<fixed;
 
    int n;
    cin >> n;
    for(int i=1; i<n; i++){
        int a, b;
        cin >> a >> b;
        graf[a].push_back(b);
        graf[b].push_back(a);
    }
    if(n == 2){cout << "1\n 1 2"; return 0;}
    dfs1(1);
    int x = 1;
    for(auto c : graf[1]){
        if(brlist[c] > (brlist[1]/2)){
            x = c;
            int par;
            par = 1;
            while(1){
                if(graf[x].size() != 2) break;
                for(auto nesto : graf[x]){
                    if(nesto != par){par = x; x = nesto; break;}
                }
            }
            break;
        }
    }
    leafs = 0;
    for(int i=1; i<=n; i++) visited[i] = 0;
    dfs3(x);
    int r = 1;
    int br=0;
    while(r+(leafs/2) <= leafs){
        br++;
        r++;
    }
    r = 1;
    cout << br << "\n";
    while(r+(leafs/2) <= leafs){
        cout << listovi[r] << " " << listovi[r+(leafs/2)] << "\n";
        r++;
    }
    return 0;
}

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 11980 KB Output is correct
2 Correct 7 ms 11980 KB Output is correct
3 Correct 7 ms 11980 KB Output is correct
4 Correct 7 ms 11980 KB Output is correct
5 Correct 7 ms 11980 KB Output is correct
6 Correct 9 ms 12064 KB Output is correct
7 Correct 8 ms 11980 KB Output is correct
8 Correct 7 ms 12064 KB Output is correct
9 Correct 7 ms 11980 KB Output is correct
10 Correct 7 ms 12060 KB Output is correct
11 Correct 8 ms 11980 KB Output is correct
12 Correct 7 ms 11996 KB Output is correct
13 Correct 8 ms 11980 KB Output is correct
14 Correct 8 ms 12064 KB Output is correct
15 Correct 7 ms 11980 KB Output is correct
16 Correct 7 ms 11980 KB Output is correct
17 Correct 7 ms 11980 KB Output is correct
18 Correct 7 ms 11980 KB Output is correct
19 Correct 8 ms 11980 KB Output is correct
20 Correct 7 ms 11980 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 11980 KB Output is correct
2 Correct 7 ms 11980 KB Output is correct
3 Correct 7 ms 11980 KB Output is correct
4 Correct 7 ms 11980 KB Output is correct
5 Correct 7 ms 11980 KB Output is correct
6 Correct 9 ms 12064 KB Output is correct
7 Correct 8 ms 11980 KB Output is correct
8 Correct 7 ms 12064 KB Output is correct
9 Correct 7 ms 11980 KB Output is correct
10 Correct 7 ms 12060 KB Output is correct
11 Correct 8 ms 11980 KB Output is correct
12 Correct 7 ms 11996 KB Output is correct
13 Correct 8 ms 11980 KB Output is correct
14 Correct 8 ms 12064 KB Output is correct
15 Correct 7 ms 11980 KB Output is correct
16 Correct 7 ms 11980 KB Output is correct
17 Correct 7 ms 11980 KB Output is correct
18 Correct 7 ms 11980 KB Output is correct
19 Correct 8 ms 11980 KB Output is correct
20 Correct 7 ms 11980 KB Output is correct
21 Correct 7 ms 12064 KB Output is correct
22 Correct 7 ms 12108 KB Output is correct
23 Correct 7 ms 12196 KB Output is correct
24 Correct 8 ms 12108 KB Output is correct
25 Correct 8 ms 12060 KB Output is correct
26 Correct 8 ms 12140 KB Output is correct
27 Correct 9 ms 12176 KB Output is correct
28 Correct 8 ms 12064 KB Output is correct
29 Correct 8 ms 12108 KB Output is correct
30 Correct 7 ms 11980 KB Output is correct
31 Correct 8 ms 12108 KB Output is correct
32 Correct 7 ms 11972 KB Output is correct
33 Correct 7 ms 11980 KB Output is correct
34 Correct 9 ms 11992 KB Output is correct
35 Correct 8 ms 12052 KB Output is correct
36 Correct 8 ms 12060 KB Output is correct
37 Correct 7 ms 12068 KB Output is correct
38 Correct 7 ms 12108 KB Output is correct
39 Correct 8 ms 12060 KB Output is correct
40 Correct 7 ms 11980 KB Output is correct
41 Correct 8 ms 12052 KB Output is correct
42 Correct 7 ms 12100 KB Output is correct
43 Correct 8 ms 12108 KB Output is correct
44 Correct 7 ms 11980 KB Output is correct
45 Correct 7 ms 11980 KB Output is correct
46 Correct 7 ms 12108 KB Output is correct
47 Correct 7 ms 12056 KB Output is correct
48 Correct 8 ms 11980 KB Output is correct
49 Correct 7 ms 12136 KB Output is correct
50 Correct 7 ms 11980 KB Output is correct
51 Correct 9 ms 12060 KB Output is correct
52 Correct 7 ms 11980 KB Output is correct
53 Correct 8 ms 12108 KB Output is correct
54 Correct 7 ms 11980 KB Output is correct
55 Correct 7 ms 11980 KB Output is correct
56 Correct 8 ms 12056 KB Output is correct
57 Correct 7 ms 12000 KB Output is correct
58 Correct 8 ms 12200 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 11980 KB Output is correct
2 Correct 7 ms 11980 KB Output is correct
3 Correct 7 ms 11980 KB Output is correct
4 Correct 7 ms 11980 KB Output is correct
5 Correct 7 ms 11980 KB Output is correct
6 Correct 9 ms 12064 KB Output is correct
7 Correct 8 ms 11980 KB Output is correct
8 Correct 7 ms 12064 KB Output is correct
9 Correct 7 ms 11980 KB Output is correct
10 Correct 7 ms 12060 KB Output is correct
11 Correct 8 ms 11980 KB Output is correct
12 Correct 7 ms 11996 KB Output is correct
13 Correct 8 ms 11980 KB Output is correct
14 Correct 8 ms 12064 KB Output is correct
15 Correct 7 ms 11980 KB Output is correct
16 Correct 7 ms 11980 KB Output is correct
17 Correct 7 ms 11980 KB Output is correct
18 Correct 7 ms 11980 KB Output is correct
19 Correct 8 ms 11980 KB Output is correct
20 Correct 7 ms 11980 KB Output is correct
21 Correct 7 ms 12064 KB Output is correct
22 Correct 7 ms 12108 KB Output is correct
23 Correct 7 ms 12196 KB Output is correct
24 Correct 8 ms 12108 KB Output is correct
25 Correct 8 ms 12060 KB Output is correct
26 Correct 8 ms 12140 KB Output is correct
27 Correct 9 ms 12176 KB Output is correct
28 Correct 8 ms 12064 KB Output is correct
29 Correct 8 ms 12108 KB Output is correct
30 Correct 7 ms 11980 KB Output is correct
31 Correct 8 ms 12108 KB Output is correct
32 Correct 7 ms 11972 KB Output is correct
33 Correct 7 ms 11980 KB Output is correct
34 Correct 9 ms 11992 KB Output is correct
35 Correct 8 ms 12052 KB Output is correct
36 Correct 8 ms 12060 KB Output is correct
37 Correct 7 ms 12068 KB Output is correct
38 Correct 7 ms 12108 KB Output is correct
39 Correct 8 ms 12060 KB Output is correct
40 Correct 7 ms 11980 KB Output is correct
41 Correct 8 ms 12052 KB Output is correct
42 Correct 7 ms 12100 KB Output is correct
43 Correct 8 ms 12108 KB Output is correct
44 Correct 7 ms 11980 KB Output is correct
45 Correct 7 ms 11980 KB Output is correct
46 Correct 7 ms 12108 KB Output is correct
47 Correct 7 ms 12056 KB Output is correct
48 Correct 8 ms 11980 KB Output is correct
49 Correct 7 ms 12136 KB Output is correct
50 Correct 7 ms 11980 KB Output is correct
51 Correct 9 ms 12060 KB Output is correct
52 Correct 7 ms 11980 KB Output is correct
53 Correct 8 ms 12108 KB Output is correct
54 Correct 7 ms 11980 KB Output is correct
55 Correct 7 ms 11980 KB Output is correct
56 Correct 8 ms 12056 KB Output is correct
57 Correct 7 ms 12000 KB Output is correct
58 Correct 8 ms 12200 KB Output is correct
59 Correct 443 ms 38128 KB Output is correct
60 Correct 511 ms 41168 KB Output is correct
61 Correct 7 ms 11980 KB Output is correct
62 Correct 7 ms 11980 KB Output is correct
63 Correct 366 ms 35436 KB Output is correct
64 Correct 9 ms 12492 KB Output is correct
65 Correct 21 ms 14352 KB Output is correct
66 Correct 199 ms 31488 KB Output is correct
67 Correct 624 ms 53608 KB Output is correct
68 Correct 607 ms 54232 KB Output is correct
69 Correct 14 ms 12876 KB Output is correct
70 Correct 89 ms 21916 KB Output is correct
71 Correct 341 ms 44120 KB Output is correct
72 Correct 363 ms 42932 KB Output is correct
73 Correct 116 ms 19712 KB Output is correct
74 Correct 552 ms 39956 KB Output is correct
75 Correct 32 ms 15436 KB Output is correct
76 Correct 357 ms 44072 KB Output is correct
77 Correct 342 ms 43912 KB Output is correct
78 Correct 36 ms 15812 KB Output is correct
79 Correct 598 ms 51236 KB Output is correct
80 Correct 9 ms 12236 KB Output is correct
81 Correct 112 ms 21912 KB Output is correct
82 Correct 428 ms 41868 KB Output is correct
83 Correct 513 ms 40012 KB Output is correct
84 Correct 512 ms 39912 KB Output is correct
85 Correct 508 ms 40052 KB Output is correct
86 Correct 487 ms 41156 KB Output is correct
87 Correct 492 ms 41028 KB Output is correct