oj.uz

Submission #137107

# Submission time Handle Problem Language Result Execution time Memory
137107 2019-07-27T05:29:12 Z silxikys Network (BOI15_net) C++14
63 / 100
 2000 ms 57680 KB 
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
 
const int maxn = 5e5+5;
int n;
vector<int> adj[maxn];
int deg[maxn];
int tin[maxn];
int pt = 0;
 
void dfs(int i, int p) {
    tin[i] = pt++;
    for (int j: adj[i]) {
        if (j == p) continue;
        dfs(j,i);
    }
}
 
int main()
{
    scanf("%d",&n);
    for (int i = 0; i < n - 1; i++) {
        int a, b; scanf("%d %d",&a,&b);
        ++deg[a];
        ++deg[b];
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    vector<int> leafs;
    leafs.reserve(n);
    int start = 1;
    for (int i = 1; i <= n; i++) {
        if (deg[i] == 1) leafs.push_back(i);
        if (deg[i] > 1) {
            start = i;
        }
    }
    for (int j: adj[start]) {
        dfs(j,j);
    }
    sort(leafs.begin(),leafs.end(),[&](auto a, auto b) {
            return tin[a] < tin[b];
            });
    int k = leafs.size();
    int m = k/2;
    printf("%d\n",(k+1)/2);
    for (int i = 0; i < (k+1)/2; i++) {
        printf("%d %d\n",leafs[i],leafs[(i+m)%k]);
    }
}

Compilation message

net.cpp: In function 'int main()':
net.cpp:22:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
     ~~~~~^~~~~~~~~
net.cpp:24:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         int a, b; scanf("%d %d",&a,&b);
                   ~~~~~^~~~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 12152 KB Output is correct
2 Correct 13 ms 12152 KB Output is correct
3 Correct 12 ms 12152 KB Output is correct
4 Correct 12 ms 12152 KB Output is correct
5 Correct 13 ms 12152 KB Output is correct
6 Correct 13 ms 12024 KB Output is correct
7 Correct 13 ms 12028 KB Output is correct
8 Correct 13 ms 12152 KB Output is correct
9 Correct 12 ms 12156 KB Output is correct
10 Correct 13 ms 12152 KB Output is correct
11 Correct 13 ms 12152 KB Output is correct
12 Correct 13 ms 12152 KB Output is correct
13 Correct 12 ms 12020 KB Output is correct
14 Correct 12 ms 12152 KB Output is correct
15 Correct 13 ms 12152 KB Output is correct
16 Correct 13 ms 12152 KB Output is correct
17 Correct 12 ms 12024 KB Output is correct
18 Correct 13 ms 12152 KB Output is correct
19 Correct 12 ms 12024 KB Output is correct
20 Correct 12 ms 12152 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 12152 KB Output is correct
2 Correct 13 ms 12152 KB Output is correct
3 Correct 12 ms 12152 KB Output is correct
4 Correct 12 ms 12152 KB Output is correct
5 Correct 13 ms 12152 KB Output is correct
6 Correct 13 ms 12024 KB Output is correct
7 Correct 13 ms 12028 KB Output is correct
8 Correct 13 ms 12152 KB Output is correct
9 Correct 12 ms 12156 KB Output is correct
10 Correct 13 ms 12152 KB Output is correct
11 Correct 13 ms 12152 KB Output is correct
12 Correct 13 ms 12152 KB Output is correct
13 Correct 12 ms 12020 KB Output is correct
14 Correct 12 ms 12152 KB Output is correct
15 Correct 13 ms 12152 KB Output is correct
16 Correct 13 ms 12152 KB Output is correct
17 Correct 12 ms 12024 KB Output is correct
18 Correct 13 ms 12152 KB Output is correct
19 Correct 12 ms 12024 KB Output is correct
20 Correct 12 ms 12152 KB Output is correct
21 Correct 12 ms 12124 KB Output is correct
22 Correct 27 ms 12280 KB Output is correct
23 Correct 14 ms 12280 KB Output is correct
24 Correct 37 ms 12152 KB Output is correct
25 Correct 14 ms 12280 KB Output is correct
26 Correct 14 ms 12152 KB Output is correct
27 Correct 15 ms 12296 KB Output is correct
28 Correct 14 ms 12152 KB Output is correct
29 Correct 14 ms 12152 KB Output is correct
30 Correct 12 ms 12024 KB Output is correct
31 Correct 14 ms 12152 KB Output is correct
32 Correct 13 ms 12152 KB Output is correct
33 Correct 12 ms 12028 KB Output is correct
34 Correct 15 ms 12152 KB Output is correct
35 Correct 14 ms 12280 KB Output is correct
36 Correct 13 ms 12024 KB Output is correct
37 Correct 14 ms 12160 KB Output is correct
38 Correct 14 ms 12152 KB Output is correct
39 Correct 13 ms 12152 KB Output is correct
40 Correct 13 ms 12152 KB Output is correct
41 Correct 13 ms 12024 KB Output is correct
42 Correct 13 ms 12024 KB Output is correct
43 Correct 13 ms 12152 KB Output is correct
44 Correct 12 ms 12152 KB Output is correct
45 Correct 13 ms 12024 KB Output is correct
46 Correct 13 ms 12152 KB Output is correct
47 Correct 12 ms 12028 KB Output is correct
48 Correct 13 ms 12152 KB Output is correct
49 Correct 13 ms 12152 KB Output is correct
50 Correct 13 ms 12104 KB Output is correct
51 Correct 13 ms 12024 KB Output is correct
52 Correct 12 ms 12152 KB Output is correct
53 Correct 13 ms 12248 KB Output is correct
54 Correct 13 ms 12152 KB Output is correct
55 Correct 13 ms 12024 KB Output is correct
56 Correct 12 ms 12152 KB Output is correct
57 Correct 13 ms 12152 KB Output is correct
58 Correct 23 ms 12152 KB Output is correct

Subtask #3
0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 12152 KB Output is correct
2 Correct 13 ms 12152 KB Output is correct
3 Correct 12 ms 12152 KB Output is correct
4 Correct 12 ms 12152 KB Output is correct
5 Correct 13 ms 12152 KB Output is correct
6 Correct 13 ms 12024 KB Output is correct
7 Correct 13 ms 12028 KB Output is correct
8 Correct 13 ms 12152 KB Output is correct
9 Correct 12 ms 12156 KB Output is correct
10 Correct 13 ms 12152 KB Output is correct
11 Correct 13 ms 12152 KB Output is correct
12 Correct 13 ms 12152 KB Output is correct
13 Correct 12 ms 12020 KB Output is correct
14 Correct 12 ms 12152 KB Output is correct
15 Correct 13 ms 12152 KB Output is correct
16 Correct 13 ms 12152 KB Output is correct
17 Correct 12 ms 12024 KB Output is correct
18 Correct 13 ms 12152 KB Output is correct
19 Correct 12 ms 12024 KB Output is correct
20 Correct 12 ms 12152 KB Output is correct
21 Correct 12 ms 12124 KB Output is correct
22 Correct 27 ms 12280 KB Output is correct
23 Correct 14 ms 12280 KB Output is correct
24 Correct 37 ms 12152 KB Output is correct
25 Correct 14 ms 12280 KB Output is correct
26 Correct 14 ms 12152 KB Output is correct
27 Correct 15 ms 12296 KB Output is correct
28 Correct 14 ms 12152 KB Output is correct
29 Correct 14 ms 12152 KB Output is correct
30 Correct 12 ms 12024 KB Output is correct
31 Correct 14 ms 12152 KB Output is correct
32 Correct 13 ms 12152 KB Output is correct
33 Correct 12 ms 12028 KB Output is correct
34 Correct 15 ms 12152 KB Output is correct
35 Correct 14 ms 12280 KB Output is correct
36 Correct 13 ms 12024 KB Output is correct
37 Correct 14 ms 12160 KB Output is correct
38 Correct 14 ms 12152 KB Output is correct
39 Correct 13 ms 12152 KB Output is correct
40 Correct 13 ms 12152 KB Output is correct
41 Correct 13 ms 12024 KB Output is correct
42 Correct 13 ms 12024 KB Output is correct
43 Correct 13 ms 12152 KB Output is correct
44 Correct 12 ms 12152 KB Output is correct
45 Correct 13 ms 12024 KB Output is correct
46 Correct 13 ms 12152 KB Output is correct
47 Correct 12 ms 12028 KB Output is correct
48 Correct 13 ms 12152 KB Output is correct
49 Correct 13 ms 12152 KB Output is correct
50 Correct 13 ms 12104 KB Output is correct
51 Correct 13 ms 12024 KB Output is correct
52 Correct 12 ms 12152 KB Output is correct
53 Correct 13 ms 12248 KB Output is correct
54 Correct 13 ms 12152 KB Output is correct
55 Correct 13 ms 12024 KB Output is correct
56 Correct 12 ms 12152 KB Output is correct
57 Correct 13 ms 12152 KB Output is correct
58 Correct 23 ms 12152 KB Output is correct
59 Correct 573 ms 36196 KB Output is correct
60 Correct 670 ms 38456 KB Output is correct
61 Correct 13 ms 12152 KB Output is correct
62 Correct 13 ms 12152 KB Output is correct
63 Correct 511 ms 33964 KB Output is correct
64 Correct 15 ms 12540 KB Output is correct
65 Correct 28 ms 13944 KB Output is correct
66 Correct 217 ms 26588 KB Output is correct
67 Correct 706 ms 57680 KB Output is correct
68 Correct 844 ms 50252 KB Output is correct
69 Correct 22 ms 12920 KB Output is correct
70 Correct 142 ms 22364 KB Output is correct
71 Execution timed out 2068 ms 38248 KB Time limit exceeded
72 Halted 0 ms 0 KB -