Submission #113191

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
113191	2019-05-24T08:32:16 Z	davitmarg	Network (BOI15_net)	C++17	100 / 100	705 ms	43380 KB

/*DavitMarg*/
#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <string>
#include <cstring>
#include <map>
#include <set>
#include <queue>
#include <iomanip>
#include <bitset>
#include <stack>
#include <cassert>
#include <iterator>
#include <ctype.h>
#include <fstream>
#define mod 1000000007ll
#define LL long long
#define LD long double
#define MP make_pair
#define PB push_back
#define all(v) v.begin (),v.end()
using namespace std;

int n,used[500005],start;
vector<int> g[500005],t;
vector<pair<int, int>> ans;

void dfs(int v, int d = 0)
{
	used[v] = 1;
	for (int i = 0; i < g[v].size(); i++)
	{
		int to = g[v][i];
		if (used[to])
			continue;
		if (g[to].size() == 1)
			t.PB(to);
	}
	for (int i = 0; i < g[v].size(); i++)
	{
		int to = g[v][i];
		if (used[to] || g[to].size() == 1)
			continue;
		dfs(to,d+1);
	}
}

int main()
{
	cin >> n;
	if (n == 0)
	{
		printf("0\n");
		return 0;
	}
	else if (n == 2)
	{
		printf("1\n");
		printf("1 2\n");
		return 0;
	}
	for (int i = 1; i < n; i++)
	{
		int a, b;
		scanf("%d%d", &a, &b);
		g[a].PB(b);
		g[b].PB(a);
	}
	for(int i=1;i<=n;i++)
		if (g[i].size() != 1)
		{
			start = i;
			break;
		}
	dfs(start);

	for (int i = 0; i + t.size() / 2 < t.size(); i++)
		ans.PB(MP(t[i], t[i+ t.size() / 2]));


	printf("%d\n",(int)ans.size());
	for (int i = 0; i < ans.size(); i++)
		printf("%d %d\n", ans[i].first, ans[i].second);

	return 0;
}

/*



*/

Compilation message

net.cpp: In function 'void dfs(int, int)':
net.cpp:33:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < g[v].size(); i++)
                  ~~^~~~~~~~~~~~~
net.cpp:41:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < g[v].size(); i++)
                  ~~^~~~~~~~~~~~~
net.cpp: In function 'int main()':
net.cpp:84:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < ans.size(); i++)
                  ~~^~~~~~~~~~~~
net.cpp:67:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &a, &b);
   ~~~~~^~~~~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	11 ms	12032 KB	Output is correct
2	Correct	11 ms	12032 KB	Output is correct
3	Correct	11 ms	12032 KB	Output is correct
4	Correct	11 ms	12032 KB	Output is correct
5	Correct	11 ms	12032 KB	Output is correct
6	Correct	13 ms	12032 KB	Output is correct
7	Correct	11 ms	12032 KB	Output is correct
8	Correct	11 ms	12032 KB	Output is correct
9	Correct	17 ms	12032 KB	Output is correct
10	Correct	11 ms	12032 KB	Output is correct
11	Correct	11 ms	12160 KB	Output is correct
12	Correct	11 ms	12032 KB	Output is correct
13	Correct	12 ms	12032 KB	Output is correct
14	Correct	12 ms	12032 KB	Output is correct
15	Correct	11 ms	11904 KB	Output is correct
16	Correct	12 ms	12032 KB	Output is correct
17	Correct	11 ms	12032 KB	Output is correct
18	Correct	11 ms	12032 KB	Output is correct
19	Correct	11 ms	12160 KB	Output is correct
20	Correct	12 ms	12032 KB	Output is correct

Subtask #2
45.0 / 45.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	11 ms	12032 KB	Output is correct
2	Correct	11 ms	12032 KB	Output is correct
3	Correct	11 ms	12032 KB	Output is correct
4	Correct	11 ms	12032 KB	Output is correct
5	Correct	11 ms	12032 KB	Output is correct
6	Correct	13 ms	12032 KB	Output is correct
7	Correct	11 ms	12032 KB	Output is correct
8	Correct	11 ms	12032 KB	Output is correct
9	Correct	17 ms	12032 KB	Output is correct
10	Correct	11 ms	12032 KB	Output is correct
11	Correct	11 ms	12160 KB	Output is correct
12	Correct	11 ms	12032 KB	Output is correct
13	Correct	12 ms	12032 KB	Output is correct
14	Correct	12 ms	12032 KB	Output is correct
15	Correct	11 ms	11904 KB	Output is correct
16	Correct	12 ms	12032 KB	Output is correct
17	Correct	11 ms	12032 KB	Output is correct
18	Correct	11 ms	12032 KB	Output is correct
19	Correct	11 ms	12160 KB	Output is correct
20	Correct	12 ms	12032 KB	Output is correct
21	Correct	11 ms	12032 KB	Output is correct
22	Correct	12 ms	12160 KB	Output is correct
23	Correct	11 ms	12156 KB	Output is correct
24	Correct	11 ms	12160 KB	Output is correct
25	Correct	11 ms	12160 KB	Output is correct
26	Correct	11 ms	12160 KB	Output is correct
27	Correct	12 ms	12160 KB	Output is correct
28	Correct	12 ms	12160 KB	Output is correct
29	Correct	12 ms	12160 KB	Output is correct
30	Correct	11 ms	12032 KB	Output is correct
31	Correct	12 ms	12160 KB	Output is correct
32	Correct	10 ms	12032 KB	Output is correct
33	Correct	11 ms	12032 KB	Output is correct
34	Correct	10 ms	12060 KB	Output is correct
35	Correct	11 ms	12032 KB	Output is correct
36	Correct	12 ms	12032 KB	Output is correct
37	Correct	11 ms	12032 KB	Output is correct
38	Correct	11 ms	12160 KB	Output is correct
39	Correct	11 ms	12032 KB	Output is correct
40	Correct	12 ms	12032 KB	Output is correct
41	Correct	11 ms	12160 KB	Output is correct
42	Correct	11 ms	12132 KB	Output is correct
43	Correct	11 ms	12160 KB	Output is correct
44	Correct	11 ms	12076 KB	Output is correct
45	Correct	11 ms	12032 KB	Output is correct
46	Correct	11 ms	12160 KB	Output is correct
47	Correct	11 ms	12032 KB	Output is correct
48	Correct	11 ms	12160 KB	Output is correct
49	Correct	15 ms	12160 KB	Output is correct
50	Correct	11 ms	12160 KB	Output is correct
51	Correct	11 ms	12032 KB	Output is correct
52	Correct	10 ms	12032 KB	Output is correct
53	Correct	12 ms	12160 KB	Output is correct
54	Correct	11 ms	12032 KB	Output is correct
55	Correct	11 ms	12160 KB	Output is correct
56	Correct	11 ms	12032 KB	Output is correct
57	Correct	11 ms	12160 KB	Output is correct
58	Correct	12 ms	12160 KB	Output is correct

Subtask #3
37.0 / 37.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	11 ms	12032 KB	Output is correct
2	Correct	11 ms	12032 KB	Output is correct
3	Correct	11 ms	12032 KB	Output is correct
4	Correct	11 ms	12032 KB	Output is correct
5	Correct	11 ms	12032 KB	Output is correct
6	Correct	13 ms	12032 KB	Output is correct
7	Correct	11 ms	12032 KB	Output is correct
8	Correct	11 ms	12032 KB	Output is correct
9	Correct	17 ms	12032 KB	Output is correct
10	Correct	11 ms	12032 KB	Output is correct
11	Correct	11 ms	12160 KB	Output is correct
12	Correct	11 ms	12032 KB	Output is correct
13	Correct	12 ms	12032 KB	Output is correct
14	Correct	12 ms	12032 KB	Output is correct
15	Correct	11 ms	11904 KB	Output is correct
16	Correct	12 ms	12032 KB	Output is correct
17	Correct	11 ms	12032 KB	Output is correct
18	Correct	11 ms	12032 KB	Output is correct
19	Correct	11 ms	12160 KB	Output is correct
20	Correct	12 ms	12032 KB	Output is correct
21	Correct	11 ms	12032 KB	Output is correct
22	Correct	12 ms	12160 KB	Output is correct
23	Correct	11 ms	12156 KB	Output is correct
24	Correct	11 ms	12160 KB	Output is correct
25	Correct	11 ms	12160 KB	Output is correct
26	Correct	11 ms	12160 KB	Output is correct
27	Correct	12 ms	12160 KB	Output is correct
28	Correct	12 ms	12160 KB	Output is correct
29	Correct	12 ms	12160 KB	Output is correct
30	Correct	11 ms	12032 KB	Output is correct
31	Correct	12 ms	12160 KB	Output is correct
32	Correct	10 ms	12032 KB	Output is correct
33	Correct	11 ms	12032 KB	Output is correct
34	Correct	10 ms	12060 KB	Output is correct
35	Correct	11 ms	12032 KB	Output is correct
36	Correct	12 ms	12032 KB	Output is correct
37	Correct	11 ms	12032 KB	Output is correct
38	Correct	11 ms	12160 KB	Output is correct
39	Correct	11 ms	12032 KB	Output is correct
40	Correct	12 ms	12032 KB	Output is correct
41	Correct	11 ms	12160 KB	Output is correct
42	Correct	11 ms	12132 KB	Output is correct
43	Correct	11 ms	12160 KB	Output is correct
44	Correct	11 ms	12076 KB	Output is correct
45	Correct	11 ms	12032 KB	Output is correct
46	Correct	11 ms	12160 KB	Output is correct
47	Correct	11 ms	12032 KB	Output is correct
48	Correct	11 ms	12160 KB	Output is correct
49	Correct	15 ms	12160 KB	Output is correct
50	Correct	11 ms	12160 KB	Output is correct
51	Correct	11 ms	12032 KB	Output is correct
52	Correct	10 ms	12032 KB	Output is correct
53	Correct	12 ms	12160 KB	Output is correct
54	Correct	11 ms	12032 KB	Output is correct
55	Correct	11 ms	12160 KB	Output is correct
56	Correct	11 ms	12032 KB	Output is correct
57	Correct	11 ms	12160 KB	Output is correct
58	Correct	12 ms	12160 KB	Output is correct
59	Correct	409 ms	33088 KB	Output is correct
60	Correct	548 ms	35472 KB	Output is correct
61	Correct	11 ms	12032 KB	Output is correct
62	Correct	11 ms	12032 KB	Output is correct
63	Correct	376 ms	31084 KB	Output is correct
64	Correct	13 ms	12416 KB	Output is correct
65	Correct	24 ms	13824 KB	Output is correct
66	Correct	182 ms	26408 KB	Output is correct
67	Correct	705 ms	42320 KB	Output is correct
68	Correct	634 ms	43380 KB	Output is correct
69	Correct	18 ms	12928 KB	Output is correct
70	Correct	102 ms	20460 KB	Output is correct
71	Correct	335 ms	37088 KB	Output is correct
72	Correct	354 ms	38108 KB	Output is correct
73	Correct	108 ms	18288 KB	Output is correct
74	Correct	568 ms	34156 KB	Output is correct
75	Correct	39 ms	15092 KB	Output is correct
76	Correct	372 ms	38668 KB	Output is correct
77	Correct	363 ms	37204 KB	Output is correct
78	Correct	40 ms	15228 KB	Output is correct
79	Correct	626 ms	40668 KB	Output is correct
80	Correct	13 ms	12288 KB	Output is correct
81	Correct	121 ms	20332 KB	Output is correct
82	Correct	430 ms	36528 KB	Output is correct
83	Correct	513 ms	34160 KB	Output is correct
84	Correct	510 ms	34032 KB	Output is correct
85	Correct	532 ms	34236 KB	Output is correct
86	Correct	556 ms	35500 KB	Output is correct
87	Correct	554 ms	35596 KB	Output is correct

Submission #113191

Compilation message

Subtask #1 18.0 / 18.0

Subtask #2 45.0 / 45.0

Subtask #3 37.0 / 37.0

Subtask #1
18.0 / 18.0

Subtask #2
45.0 / 45.0

Subtask #3
37.0 / 37.0