Submission #102149

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
102149	2019-03-22T20:20:38 Z	Leonardo_Paes	Network (BOI15_net)	C++11	100 / 100	675 ms	40976 KB

#include <bits/stdc++.h>

using namespace std;

const int MAXN = 5e5 + 10;

int v[MAXN], cnt;

vector<int> grafo[MAXN];

int read()
{
	int x=0,f=1;char c=getchar();
	while (c<'0'||c>'9') {if (c=='-') f=-1;c=getchar();}
	while (c>='0'&&c<='9') x=(x<<1)+(x<<3)+(c^48),c=getchar();
	return x*f;
}

void dfs(int u, int p)
{
	for (int i=0; i<grafo[u].size(); i++){
        int v = grafo[u][i];
		if (v == p) continue;
		dfs(v, u);
	}

	if (grafo[u].size() == 1) v[++cnt] = u;
}

int main(){
    int n=read();

    for(int i=1; i<n; i++){
        int a, b;

        a=read();
        b=read();

        grafo[a].push_back(b);
        grafo[b].push_back(a);
    }

    for(int i=1; i<=n; i++){
        if(grafo[i].size()>1){
            dfs(i, 0);
            break;
        }
    }

    int ans = (cnt+1)/2;

    cout << ans << "\n";

    for(int i=1; i<ans; i++){
        cout << v[i] << " " << v[i+ans] << "\n";
    }
    if(cnt&1){
        cout << v[ans] << " " << v[1] << "\n";
    }
    else{
        cout << v[ans] << " " << v[cnt] << "\n";
    }
    return 0;
}

Compilation message

net.cpp: In function 'void dfs(int, int)':
net.cpp:21:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i=0; i<grafo[u].size(); i++){
                ~^~~~~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	12 ms	12032 KB	Output is correct
2	Correct	12 ms	12032 KB	Output is correct
3	Correct	12 ms	12032 KB	Output is correct
4	Correct	11 ms	12032 KB	Output is correct
5	Correct	12 ms	12160 KB	Output is correct
6	Correct	12 ms	12032 KB	Output is correct
7	Correct	11 ms	12032 KB	Output is correct
8	Correct	14 ms	12032 KB	Output is correct
9	Correct	11 ms	12032 KB	Output is correct
10	Correct	13 ms	12160 KB	Output is correct
11	Correct	12 ms	12160 KB	Output is correct
12	Correct	11 ms	12032 KB	Output is correct
13	Correct	11 ms	12032 KB	Output is correct
14	Correct	12 ms	12032 KB	Output is correct
15	Correct	13 ms	12004 KB	Output is correct
16	Correct	14 ms	12032 KB	Output is correct
17	Correct	16 ms	12160 KB	Output is correct
18	Correct	14 ms	12080 KB	Output is correct
19	Correct	13 ms	12032 KB	Output is correct
20	Correct	13 ms	12032 KB	Output is correct

Subtask #2
45.0 / 45.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	12 ms	12032 KB	Output is correct
2	Correct	12 ms	12032 KB	Output is correct
3	Correct	12 ms	12032 KB	Output is correct
4	Correct	11 ms	12032 KB	Output is correct
5	Correct	12 ms	12160 KB	Output is correct
6	Correct	12 ms	12032 KB	Output is correct
7	Correct	11 ms	12032 KB	Output is correct
8	Correct	14 ms	12032 KB	Output is correct
9	Correct	11 ms	12032 KB	Output is correct
10	Correct	13 ms	12160 KB	Output is correct
11	Correct	12 ms	12160 KB	Output is correct
12	Correct	11 ms	12032 KB	Output is correct
13	Correct	11 ms	12032 KB	Output is correct
14	Correct	12 ms	12032 KB	Output is correct
15	Correct	13 ms	12004 KB	Output is correct
16	Correct	14 ms	12032 KB	Output is correct
17	Correct	16 ms	12160 KB	Output is correct
18	Correct	14 ms	12080 KB	Output is correct
19	Correct	13 ms	12032 KB	Output is correct
20	Correct	13 ms	12032 KB	Output is correct
21	Correct	11 ms	12032 KB	Output is correct
22	Correct	13 ms	12160 KB	Output is correct
23	Correct	12 ms	12160 KB	Output is correct
24	Correct	14 ms	12288 KB	Output is correct
25	Correct	11 ms	12160 KB	Output is correct
26	Correct	15 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	13 ms	12160 KB	Output is correct
32	Correct	12 ms	12032 KB	Output is correct
33	Correct	16 ms	12032 KB	Output is correct
34	Correct	14 ms	12032 KB	Output is correct
35	Correct	12 ms	12032 KB	Output is correct
36	Correct	13 ms	12160 KB	Output is correct
37	Correct	12 ms	12160 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	12032 KB	Output is correct
42	Correct	12 ms	12160 KB	Output is correct
43	Correct	12 ms	12160 KB	Output is correct
44	Correct	13 ms	12032 KB	Output is correct
45	Correct	12 ms	12032 KB	Output is correct
46	Correct	14 ms	12032 KB	Output is correct
47	Correct	12 ms	12032 KB	Output is correct
48	Correct	12 ms	12032 KB	Output is correct
49	Correct	14 ms	12160 KB	Output is correct
50	Correct	11 ms	12032 KB	Output is correct
51	Correct	12 ms	12032 KB	Output is correct
52	Correct	12 ms	12032 KB	Output is correct
53	Correct	13 ms	12160 KB	Output is correct
54	Correct	16 ms	12024 KB	Output is correct
55	Correct	12 ms	12160 KB	Output is correct
56	Correct	11 ms	12032 KB	Output is correct
57	Correct	12 ms	12160 KB	Output is correct
58	Correct	14 ms	12160 KB	Output is correct

Subtask #3
37.0 / 37.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	12 ms	12032 KB	Output is correct
2	Correct	12 ms	12032 KB	Output is correct
3	Correct	12 ms	12032 KB	Output is correct
4	Correct	11 ms	12032 KB	Output is correct
5	Correct	12 ms	12160 KB	Output is correct
6	Correct	12 ms	12032 KB	Output is correct
7	Correct	11 ms	12032 KB	Output is correct
8	Correct	14 ms	12032 KB	Output is correct
9	Correct	11 ms	12032 KB	Output is correct
10	Correct	13 ms	12160 KB	Output is correct
11	Correct	12 ms	12160 KB	Output is correct
12	Correct	11 ms	12032 KB	Output is correct
13	Correct	11 ms	12032 KB	Output is correct
14	Correct	12 ms	12032 KB	Output is correct
15	Correct	13 ms	12004 KB	Output is correct
16	Correct	14 ms	12032 KB	Output is correct
17	Correct	16 ms	12160 KB	Output is correct
18	Correct	14 ms	12080 KB	Output is correct
19	Correct	13 ms	12032 KB	Output is correct
20	Correct	13 ms	12032 KB	Output is correct
21	Correct	11 ms	12032 KB	Output is correct
22	Correct	13 ms	12160 KB	Output is correct
23	Correct	12 ms	12160 KB	Output is correct
24	Correct	14 ms	12288 KB	Output is correct
25	Correct	11 ms	12160 KB	Output is correct
26	Correct	15 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	13 ms	12160 KB	Output is correct
32	Correct	12 ms	12032 KB	Output is correct
33	Correct	16 ms	12032 KB	Output is correct
34	Correct	14 ms	12032 KB	Output is correct
35	Correct	12 ms	12032 KB	Output is correct
36	Correct	13 ms	12160 KB	Output is correct
37	Correct	12 ms	12160 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	12032 KB	Output is correct
42	Correct	12 ms	12160 KB	Output is correct
43	Correct	12 ms	12160 KB	Output is correct
44	Correct	13 ms	12032 KB	Output is correct
45	Correct	12 ms	12032 KB	Output is correct
46	Correct	14 ms	12032 KB	Output is correct
47	Correct	12 ms	12032 KB	Output is correct
48	Correct	12 ms	12032 KB	Output is correct
49	Correct	14 ms	12160 KB	Output is correct
50	Correct	11 ms	12032 KB	Output is correct
51	Correct	12 ms	12032 KB	Output is correct
52	Correct	12 ms	12032 KB	Output is correct
53	Correct	13 ms	12160 KB	Output is correct
54	Correct	16 ms	12024 KB	Output is correct
55	Correct	12 ms	12160 KB	Output is correct
56	Correct	11 ms	12032 KB	Output is correct
57	Correct	12 ms	12160 KB	Output is correct
58	Correct	14 ms	12160 KB	Output is correct
59	Correct	458 ms	29972 KB	Output is correct
60	Correct	513 ms	32120 KB	Output is correct
61	Correct	12 ms	12032 KB	Output is correct
62	Correct	20 ms	12032 KB	Output is correct
63	Correct	387 ms	28144 KB	Output is correct
64	Correct	16 ms	12412 KB	Output is correct
65	Correct	23 ms	13696 KB	Output is correct
66	Correct	194 ms	25720 KB	Output is correct
67	Correct	599 ms	40440 KB	Output is correct
68	Correct	559 ms	40976 KB	Output is correct
69	Correct	18 ms	12672 KB	Output is correct
70	Correct	107 ms	19092 KB	Output is correct
71	Correct	358 ms	35044 KB	Output is correct
72	Correct	351 ms	34180 KB	Output is correct
73	Correct	142 ms	17444 KB	Output is correct
74	Correct	621 ms	30968 KB	Output is correct
75	Correct	51 ms	14584 KB	Output is correct
76	Correct	483 ms	34872 KB	Output is correct
77	Correct	311 ms	34904 KB	Output is correct
78	Correct	38 ms	14924 KB	Output is correct
79	Correct	601 ms	38580 KB	Output is correct
80	Correct	13 ms	12288 KB	Output is correct
81	Correct	125 ms	19096 KB	Output is correct
82	Correct	449 ms	33068 KB	Output is correct
83	Correct	544 ms	30940 KB	Output is correct
84	Correct	596 ms	31000 KB	Output is correct
85	Correct	675 ms	30924 KB	Output is correct
86	Correct	536 ms	31996 KB	Output is correct
87	Correct	546 ms	31964 KB	Output is correct

Submission #102149

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