oj.uz

Submission #51613

# Submission time Handle Problem Language Result Execution time Memory
51613 2018-06-19T08:06:30 Z okaybody10 Network (BOI15_net) C++
100 / 100
 673 ms 155376 KB 
#include <bits/stdc++.h>
using namespace std;
vector<int> v[600005],ans;
void dfs(int e,int s)
{
    if(v[e].size()==1) { ans.push_back(e); return; }
    int sz=v[e].size();
    for(int i=0;i<sz;i++)
    {
        if(v[e][i]==s) continue;
        dfs(v[e][i],e);
    }
}
int main()
{
    int n; scanf("%d",&n);
    for(int i=0;i<n-1;i++)
    {
        int x,y; scanf("%d %d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    int firstdfs;
    for(int i=1;i<=n;i++) if(v[i].size()>=2) { firstdfs=i; break;}
    dfs(firstdfs,-1);
    int sz=ans.size();
    printf("%d\n",sz/2+sz%2);
    for(int i=0;i+sz/2<sz;i++) printf("%d %d\n",ans[i],ans[i+sz/2]);
    return 0;
}

Compilation message

net.cpp: In function 'int main()':
net.cpp:16:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     int n; scanf("%d",&n);
            ~~~~~^~~~~~~~~
net.cpp:19:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         int x,y; scanf("%d %d",&x,&y);
                  ~~~~~^~~~~~~~~~~~~~~
net.cpp:25:8: warning: 'firstdfs' may be used uninitialized in this function [-Wmaybe-uninitialized]
     dfs(firstdfs,-1);
     ~~~^~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 14328 KB Output is correct
2 Correct 17 ms 14568 KB Output is correct
3 Correct 13 ms 14568 KB Output is correct
4 Correct 16 ms 14572 KB Output is correct
5 Correct 16 ms 14696 KB Output is correct
6 Correct 15 ms 14696 KB Output is correct
7 Correct 15 ms 14736 KB Output is correct
8 Correct 13 ms 14736 KB Output is correct
9 Correct 13 ms 14740 KB Output is correct
10 Correct 15 ms 14740 KB Output is correct
11 Correct 13 ms 14740 KB Output is correct
12 Correct 15 ms 14740 KB Output is correct
13 Correct 14 ms 14740 KB Output is correct
14 Correct 16 ms 14740 KB Output is correct
15 Correct 14 ms 14740 KB Output is correct
16 Correct 16 ms 14740 KB Output is correct
17 Correct 18 ms 14744 KB Output is correct
18 Correct 17 ms 14744 KB Output is correct
19 Correct 15 ms 14752 KB Output is correct
20 Correct 16 ms 14756 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 14328 KB Output is correct
2 Correct 17 ms 14568 KB Output is correct
3 Correct 13 ms 14568 KB Output is correct
4 Correct 16 ms 14572 KB Output is correct
5 Correct 16 ms 14696 KB Output is correct
6 Correct 15 ms 14696 KB Output is correct
7 Correct 15 ms 14736 KB Output is correct
8 Correct 13 ms 14736 KB Output is correct
9 Correct 13 ms 14740 KB Output is correct
10 Correct 15 ms 14740 KB Output is correct
11 Correct 13 ms 14740 KB Output is correct
12 Correct 15 ms 14740 KB Output is correct
13 Correct 14 ms 14740 KB Output is correct
14 Correct 16 ms 14740 KB Output is correct
15 Correct 14 ms 14740 KB Output is correct
16 Correct 16 ms 14740 KB Output is correct
17 Correct 18 ms 14744 KB Output is correct
18 Correct 17 ms 14744 KB Output is correct
19 Correct 15 ms 14752 KB Output is correct
20 Correct 16 ms 14756 KB Output is correct
21 Correct 13 ms 14756 KB Output is correct
22 Correct 15 ms 14764 KB Output is correct
23 Correct 17 ms 14800 KB Output is correct
24 Correct 15 ms 14836 KB Output is correct
25 Correct 15 ms 14876 KB Output is correct
26 Correct 14 ms 14888 KB Output is correct
27 Correct 20 ms 14900 KB Output is correct
28 Correct 16 ms 14920 KB Output is correct
29 Correct 14 ms 14940 KB Output is correct
30 Correct 14 ms 14972 KB Output is correct
31 Correct 17 ms 14976 KB Output is correct
32 Correct 14 ms 14996 KB Output is correct
33 Correct 15 ms 14996 KB Output is correct
34 Correct 13 ms 14996 KB Output is correct
35 Correct 16 ms 15008 KB Output is correct
36 Correct 14 ms 15012 KB Output is correct
37 Correct 16 ms 15016 KB Output is correct
38 Correct 14 ms 15024 KB Output is correct
39 Correct 14 ms 15024 KB Output is correct
40 Correct 13 ms 15052 KB Output is correct
41 Correct 13 ms 15052 KB Output is correct
42 Correct 16 ms 15060 KB Output is correct
43 Correct 14 ms 15168 KB Output is correct
44 Correct 13 ms 15168 KB Output is correct
45 Correct 15 ms 15168 KB Output is correct
46 Correct 14 ms 15168 KB Output is correct
47 Correct 14 ms 15168 KB Output is correct
48 Correct 14 ms 15168 KB Output is correct
49 Correct 17 ms 15168 KB Output is correct
50 Correct 14 ms 15168 KB Output is correct
51 Correct 14 ms 15168 KB Output is correct
52 Correct 17 ms 15168 KB Output is correct
53 Correct 17 ms 15168 KB Output is correct
54 Correct 16 ms 15168 KB Output is correct
55 Correct 14 ms 15168 KB Output is correct
56 Correct 13 ms 15168 KB Output is correct
57 Correct 14 ms 15168 KB Output is correct
58 Correct 15 ms 15168 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 14328 KB Output is correct
2 Correct 17 ms 14568 KB Output is correct
3 Correct 13 ms 14568 KB Output is correct
4 Correct 16 ms 14572 KB Output is correct
5 Correct 16 ms 14696 KB Output is correct
6 Correct 15 ms 14696 KB Output is correct
7 Correct 15 ms 14736 KB Output is correct
8 Correct 13 ms 14736 KB Output is correct
9 Correct 13 ms 14740 KB Output is correct
10 Correct 15 ms 14740 KB Output is correct
11 Correct 13 ms 14740 KB Output is correct
12 Correct 15 ms 14740 KB Output is correct
13 Correct 14 ms 14740 KB Output is correct
14 Correct 16 ms 14740 KB Output is correct
15 Correct 14 ms 14740 KB Output is correct
16 Correct 16 ms 14740 KB Output is correct
17 Correct 18 ms 14744 KB Output is correct
18 Correct 17 ms 14744 KB Output is correct
19 Correct 15 ms 14752 KB Output is correct
20 Correct 16 ms 14756 KB Output is correct
21 Correct 13 ms 14756 KB Output is correct
22 Correct 15 ms 14764 KB Output is correct
23 Correct 17 ms 14800 KB Output is correct
24 Correct 15 ms 14836 KB Output is correct
25 Correct 15 ms 14876 KB Output is correct
26 Correct 14 ms 14888 KB Output is correct
27 Correct 20 ms 14900 KB Output is correct
28 Correct 16 ms 14920 KB Output is correct
29 Correct 14 ms 14940 KB Output is correct
30 Correct 14 ms 14972 KB Output is correct
31 Correct 17 ms 14976 KB Output is correct
32 Correct 14 ms 14996 KB Output is correct
33 Correct 15 ms 14996 KB Output is correct
34 Correct 13 ms 14996 KB Output is correct
35 Correct 16 ms 15008 KB Output is correct
36 Correct 14 ms 15012 KB Output is correct
37 Correct 16 ms 15016 KB Output is correct
38 Correct 14 ms 15024 KB Output is correct
39 Correct 14 ms 15024 KB Output is correct
40 Correct 13 ms 15052 KB Output is correct
41 Correct 13 ms 15052 KB Output is correct
42 Correct 16 ms 15060 KB Output is correct
43 Correct 14 ms 15168 KB Output is correct
44 Correct 13 ms 15168 KB Output is correct
45 Correct 15 ms 15168 KB Output is correct
46 Correct 14 ms 15168 KB Output is correct
47 Correct 14 ms 15168 KB Output is correct
48 Correct 14 ms 15168 KB Output is correct
49 Correct 17 ms 15168 KB Output is correct
50 Correct 14 ms 15168 KB Output is correct
51 Correct 14 ms 15168 KB Output is correct
52 Correct 17 ms 15168 KB Output is correct
53 Correct 17 ms 15168 KB Output is correct
54 Correct 16 ms 15168 KB Output is correct
55 Correct 14 ms 15168 KB Output is correct
56 Correct 13 ms 15168 KB Output is correct
57 Correct 14 ms 15168 KB Output is correct
58 Correct 15 ms 15168 KB Output is correct
59 Correct 449 ms 39080 KB Output is correct
60 Correct 603 ms 47900 KB Output is correct
61 Correct 13 ms 47900 KB Output is correct
62 Correct 15 ms 47900 KB Output is correct
63 Correct 431 ms 49288 KB Output is correct
64 Correct 17 ms 49288 KB Output is correct
65 Correct 28 ms 49288 KB Output is correct
66 Correct 196 ms 49288 KB Output is correct
67 Correct 623 ms 70464 KB Output is correct
68 Correct 673 ms 78016 KB Output is correct
69 Correct 22 ms 78016 KB Output is correct
70 Correct 109 ms 78016 KB Output is correct
71 Correct 370 ms 80912 KB Output is correct
72 Correct 389 ms 86520 KB Output is correct
73 Correct 126 ms 86520 KB Output is correct
74 Correct 567 ms 91580 KB Output is correct
75 Correct 64 ms 91580 KB Output is correct
76 Correct 404 ms 102672 KB Output is correct
77 Correct 427 ms 109296 KB Output is correct
78 Correct 61 ms 109296 KB Output is correct
79 Correct 661 ms 120180 KB Output is correct
80 Correct 16 ms 120180 KB Output is correct
81 Correct 144 ms 120180 KB Output is correct
82 Correct 461 ms 123256 KB Output is correct
83 Correct 544 ms 127960 KB Output is correct
84 Correct 605 ms 134604 KB Output is correct
85 Correct 570 ms 141156 KB Output is correct
86 Correct 573 ms 148820 KB Output is correct
87 Correct 565 ms 155376 KB Output is correct