Submission #197949

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
197949	2020-01-24T11:59:13 Z	dndhk	Network (BOI15_net)	C++14	100 / 100	747 ms	51824 KB

#include <bits/stdc++.h>

#define pb push_back

using namespace std;

const int MAX_N = 500000;

int N;
vector<int> gp[MAX_N+1];
int r;
vector<int> v;
int p[MAX_N+1], sz[MAX_N+1];

void dfs(int x){
	sz[x] = 1;
	for(int i : gp[x]){
		if(i==p[x])	continue;
		p[i] = x;
		dfs(i);
		sz[x]+=sz[i];
	}
}

void dfs2(int x){
	if(sz[x]==1){
		v.pb(x);
	}
	for(int i : gp[x]){
		if(i==p[x])	continue;
		dfs2(i);
	}
}

int main(){
	scanf("%d", &N);
	for(int i=1; i<N; i++){
		int a, b; scanf("%d%d", &a, &b);
		gp[a].pb(b);
		gp[b].pb(a);
	}
	for(int i=1; i<=N; i++){
		if(gp[i].size()>=2){
			r = i;
			break;
		}
	}
	dfs(r);
	dfs2(r);
	printf("%d\n", (v.size()+1)/2);
	int l = v.size()/2;
	for(int i=0; i<=(v.size()-1)/2; i++){
		printf("%d %d\n", v[i], v[i+l]);
	}
}

Compilation message

net.cpp: In function 'int main()':
net.cpp:50:31: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::vector<int>::size_type {aka long unsigned int}' [-Wformat=]
  printf("%d\n", (v.size()+1)/2);
                 ~~~~~~~~~~~~~~^
net.cpp:52:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0; i<=(v.size()-1)/2; i++){
               ~^~~~~~~~~~~~~~~~
net.cpp:36:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &N);
  ~~~~~^~~~~~~~~~
net.cpp:38:18: 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	13 ms	12152 KB	Output is correct
2	Correct	13 ms	12152 KB	Output is correct
3	Correct	13 ms	12280 KB	Output is correct
4	Correct	12 ms	12028 KB	Output is correct
5	Correct	13 ms	12152 KB	Output is correct
6	Correct	12 ms	12024 KB	Output is correct
7	Correct	13 ms	12152 KB	Output is correct
8	Correct	13 ms	12024 KB	Output is correct
9	Correct	13 ms	12144 KB	Output is correct
10	Correct	13 ms	12152 KB	Output is correct
11	Correct	13 ms	12028 KB	Output is correct
12	Correct	13 ms	12024 KB	Output is correct
13	Correct	13 ms	12024 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	13 ms	12152 KB	Output is correct
18	Correct	13 ms	12024 KB	Output is correct
19	Correct	13 ms	12152 KB	Output is correct
20	Correct	13 ms	12024 KB	Output is correct

Subtask #2
45.0 / 45.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	13 ms	12152 KB	Output is correct
2	Correct	13 ms	12152 KB	Output is correct
3	Correct	13 ms	12280 KB	Output is correct
4	Correct	12 ms	12028 KB	Output is correct
5	Correct	13 ms	12152 KB	Output is correct
6	Correct	12 ms	12024 KB	Output is correct
7	Correct	13 ms	12152 KB	Output is correct
8	Correct	13 ms	12024 KB	Output is correct
9	Correct	13 ms	12144 KB	Output is correct
10	Correct	13 ms	12152 KB	Output is correct
11	Correct	13 ms	12028 KB	Output is correct
12	Correct	13 ms	12024 KB	Output is correct
13	Correct	13 ms	12024 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	13 ms	12152 KB	Output is correct
18	Correct	13 ms	12024 KB	Output is correct
19	Correct	13 ms	12152 KB	Output is correct
20	Correct	13 ms	12024 KB	Output is correct
21	Correct	13 ms	12152 KB	Output is correct
22	Correct	14 ms	12152 KB	Output is correct
23	Correct	14 ms	12156 KB	Output is correct
24	Correct	14 ms	12152 KB	Output is correct
25	Correct	14 ms	12152 KB	Output is correct
26	Correct	14 ms	12152 KB	Output is correct
27	Correct	14 ms	12152 KB	Output is correct
28	Correct	14 ms	12280 KB	Output is correct
29	Correct	14 ms	12152 KB	Output is correct
30	Correct	13 ms	12024 KB	Output is correct
31	Correct	14 ms	12280 KB	Output is correct
32	Correct	13 ms	12152 KB	Output is correct
33	Correct	13 ms	12152 KB	Output is correct
34	Correct	12 ms	12152 KB	Output is correct
35	Correct	13 ms	12124 KB	Output is correct
36	Correct	13 ms	12152 KB	Output is correct
37	Correct	13 ms	12152 KB	Output is correct
38	Correct	13 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	12156 KB	Output is correct
43	Correct	16 ms	12152 KB	Output is correct
44	Correct	15 ms	12024 KB	Output is correct
45	Correct	15 ms	12024 KB	Output is correct
46	Correct	14 ms	12156 KB	Output is correct
47	Correct	13 ms	11896 KB	Output is correct
48	Correct	13 ms	12024 KB	Output is correct
49	Correct	13 ms	12152 KB	Output is correct
50	Correct	13 ms	12152 KB	Output is correct
51	Correct	13 ms	12024 KB	Output is correct
52	Correct	13 ms	12024 KB	Output is correct
53	Correct	13 ms	12124 KB	Output is correct
54	Correct	13 ms	12024 KB	Output is correct
55	Correct	13 ms	12024 KB	Output is correct
56	Correct	16 ms	12152 KB	Output is correct
57	Correct	12 ms	12152 KB	Output is correct
58	Correct	14 ms	12280 KB	Output is correct

Subtask #3
37.0 / 37.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	13 ms	12152 KB	Output is correct
2	Correct	13 ms	12152 KB	Output is correct
3	Correct	13 ms	12280 KB	Output is correct
4	Correct	12 ms	12028 KB	Output is correct
5	Correct	13 ms	12152 KB	Output is correct
6	Correct	12 ms	12024 KB	Output is correct
7	Correct	13 ms	12152 KB	Output is correct
8	Correct	13 ms	12024 KB	Output is correct
9	Correct	13 ms	12144 KB	Output is correct
10	Correct	13 ms	12152 KB	Output is correct
11	Correct	13 ms	12028 KB	Output is correct
12	Correct	13 ms	12024 KB	Output is correct
13	Correct	13 ms	12024 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	13 ms	12152 KB	Output is correct
18	Correct	13 ms	12024 KB	Output is correct
19	Correct	13 ms	12152 KB	Output is correct
20	Correct	13 ms	12024 KB	Output is correct
21	Correct	13 ms	12152 KB	Output is correct
22	Correct	14 ms	12152 KB	Output is correct
23	Correct	14 ms	12156 KB	Output is correct
24	Correct	14 ms	12152 KB	Output is correct
25	Correct	14 ms	12152 KB	Output is correct
26	Correct	14 ms	12152 KB	Output is correct
27	Correct	14 ms	12152 KB	Output is correct
28	Correct	14 ms	12280 KB	Output is correct
29	Correct	14 ms	12152 KB	Output is correct
30	Correct	13 ms	12024 KB	Output is correct
31	Correct	14 ms	12280 KB	Output is correct
32	Correct	13 ms	12152 KB	Output is correct
33	Correct	13 ms	12152 KB	Output is correct
34	Correct	12 ms	12152 KB	Output is correct
35	Correct	13 ms	12124 KB	Output is correct
36	Correct	13 ms	12152 KB	Output is correct
37	Correct	13 ms	12152 KB	Output is correct
38	Correct	13 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	12156 KB	Output is correct
43	Correct	16 ms	12152 KB	Output is correct
44	Correct	15 ms	12024 KB	Output is correct
45	Correct	15 ms	12024 KB	Output is correct
46	Correct	14 ms	12156 KB	Output is correct
47	Correct	13 ms	11896 KB	Output is correct
48	Correct	13 ms	12024 KB	Output is correct
49	Correct	13 ms	12152 KB	Output is correct
50	Correct	13 ms	12152 KB	Output is correct
51	Correct	13 ms	12024 KB	Output is correct
52	Correct	13 ms	12024 KB	Output is correct
53	Correct	13 ms	12124 KB	Output is correct
54	Correct	13 ms	12024 KB	Output is correct
55	Correct	13 ms	12024 KB	Output is correct
56	Correct	16 ms	12152 KB	Output is correct
57	Correct	12 ms	12152 KB	Output is correct
58	Correct	14 ms	12280 KB	Output is correct
59	Correct	481 ms	39784 KB	Output is correct
60	Correct	589 ms	42872 KB	Output is correct
61	Correct	13 ms	12152 KB	Output is correct
62	Correct	13 ms	12152 KB	Output is correct
63	Correct	417 ms	36848 KB	Output is correct
64	Correct	16 ms	12536 KB	Output is correct
65	Correct	29 ms	14200 KB	Output is correct
66	Correct	247 ms	29500 KB	Output is correct
67	Correct	747 ms	50944 KB	Output is correct
68	Correct	740 ms	51824 KB	Output is correct
69	Correct	21 ms	13048 KB	Output is correct
70	Correct	124 ms	22600 KB	Output is correct
71	Correct	397 ms	45932 KB	Output is correct
72	Correct	426 ms	44748 KB	Output is correct
73	Correct	151 ms	20256 KB	Output is correct
74	Correct	621 ms	41788 KB	Output is correct
75	Correct	47 ms	15732 KB	Output is correct
76	Correct	426 ms	45524 KB	Output is correct
77	Correct	405 ms	45764 KB	Output is correct
78	Correct	58 ms	15992 KB	Output is correct
79	Correct	747 ms	49148 KB	Output is correct
80	Correct	15 ms	12408 KB	Output is correct
81	Correct	161 ms	22852 KB	Output is correct
82	Correct	514 ms	43576 KB	Output is correct
83	Correct	614 ms	41840 KB	Output is correct
84	Correct	606 ms	41844 KB	Output is correct
85	Correct	613 ms	41608 KB	Output is correct
86	Correct	578 ms	42724 KB	Output is correct
87	Correct	588 ms	42868 KB	Output is correct

Submission #197949

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