Submission #102148

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
102148	2019-03-22T20:18:51 Z	Leonardo_Paes	Network (BOI15_net)	C++11	100 / 100	680 ms	40956 KB

#include <bits/stdc++.h>

using namespace std;

const int MAXN = 5e5 + 100;

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(){
    ios_base::sync_with_stdio(false);cin.tie(NULL);
    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];
    }
    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	15 ms	12160 KB	Output is correct
2	Correct	14 ms	12160 KB	Output is correct
3	Correct	14 ms	12124 KB	Output is correct
4	Correct	16 ms	12032 KB	Output is correct
5	Correct	12 ms	12160 KB	Output is correct
6	Correct	15 ms	12172 KB	Output is correct
7	Correct	18 ms	12160 KB	Output is correct
8	Correct	12 ms	12032 KB	Output is correct
9	Correct	14 ms	12160 KB	Output is correct
10	Correct	13 ms	12160 KB	Output is correct
11	Correct	13 ms	12288 KB	Output is correct
12	Correct	15 ms	12160 KB	Output is correct
13	Correct	13 ms	12160 KB	Output is correct
14	Correct	12 ms	12032 KB	Output is correct
15	Correct	13 ms	12160 KB	Output is correct
16	Correct	14 ms	12152 KB	Output is correct
17	Correct	12 ms	12160 KB	Output is correct
18	Correct	11 ms	12160 KB	Output is correct
19	Correct	13 ms	12160 KB	Output is correct
20	Correct	12 ms	12160 KB	Output is correct

Subtask #2
45.0 / 45.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	15 ms	12160 KB	Output is correct
2	Correct	14 ms	12160 KB	Output is correct
3	Correct	14 ms	12124 KB	Output is correct
4	Correct	16 ms	12032 KB	Output is correct
5	Correct	12 ms	12160 KB	Output is correct
6	Correct	15 ms	12172 KB	Output is correct
7	Correct	18 ms	12160 KB	Output is correct
8	Correct	12 ms	12032 KB	Output is correct
9	Correct	14 ms	12160 KB	Output is correct
10	Correct	13 ms	12160 KB	Output is correct
11	Correct	13 ms	12288 KB	Output is correct
12	Correct	15 ms	12160 KB	Output is correct
13	Correct	13 ms	12160 KB	Output is correct
14	Correct	12 ms	12032 KB	Output is correct
15	Correct	13 ms	12160 KB	Output is correct
16	Correct	14 ms	12152 KB	Output is correct
17	Correct	12 ms	12160 KB	Output is correct
18	Correct	11 ms	12160 KB	Output is correct
19	Correct	13 ms	12160 KB	Output is correct
20	Correct	12 ms	12160 KB	Output is correct
21	Correct	11 ms	12160 KB	Output is correct
22	Correct	12 ms	12156 KB	Output is correct
23	Correct	11 ms	12160 KB	Output is correct
24	Correct	12 ms	12160 KB	Output is correct
25	Correct	11 ms	12160 KB	Output is correct
26	Correct	12 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	12160 KB	Output is correct
31	Correct	12 ms	12160 KB	Output is correct
32	Correct	17 ms	12160 KB	Output is correct
33	Correct	13 ms	12160 KB	Output is correct
34	Correct	15 ms	12160 KB	Output is correct
35	Correct	12 ms	12160 KB	Output is correct
36	Correct	11 ms	12160 KB	Output is correct
37	Correct	11 ms	12160 KB	Output is correct
38	Correct	11 ms	12160 KB	Output is correct
39	Correct	12 ms	12160 KB	Output is correct
40	Correct	12 ms	12032 KB	Output is correct
41	Correct	11 ms	12140 KB	Output is correct
42	Correct	11 ms	12032 KB	Output is correct
43	Correct	13 ms	12160 KB	Output is correct
44	Correct	12 ms	12160 KB	Output is correct
45	Correct	12 ms	12160 KB	Output is correct
46	Correct	13 ms	12160 KB	Output is correct
47	Correct	12 ms	12160 KB	Output is correct
48	Correct	12 ms	12160 KB	Output is correct
49	Correct	17 ms	12288 KB	Output is correct
50	Correct	11 ms	12032 KB	Output is correct
51	Correct	13 ms	12160 KB	Output is correct
52	Correct	13 ms	12160 KB	Output is correct
53	Correct	12 ms	12160 KB	Output is correct
54	Correct	12 ms	12032 KB	Output is correct
55	Correct	12 ms	12160 KB	Output is correct
56	Correct	12 ms	12160 KB	Output is correct
57	Correct	13 ms	12160 KB	Output is correct
58	Correct	15 ms	12288 KB	Output is correct

Subtask #3
37.0 / 37.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	15 ms	12160 KB	Output is correct
2	Correct	14 ms	12160 KB	Output is correct
3	Correct	14 ms	12124 KB	Output is correct
4	Correct	16 ms	12032 KB	Output is correct
5	Correct	12 ms	12160 KB	Output is correct
6	Correct	15 ms	12172 KB	Output is correct
7	Correct	18 ms	12160 KB	Output is correct
8	Correct	12 ms	12032 KB	Output is correct
9	Correct	14 ms	12160 KB	Output is correct
10	Correct	13 ms	12160 KB	Output is correct
11	Correct	13 ms	12288 KB	Output is correct
12	Correct	15 ms	12160 KB	Output is correct
13	Correct	13 ms	12160 KB	Output is correct
14	Correct	12 ms	12032 KB	Output is correct
15	Correct	13 ms	12160 KB	Output is correct
16	Correct	14 ms	12152 KB	Output is correct
17	Correct	12 ms	12160 KB	Output is correct
18	Correct	11 ms	12160 KB	Output is correct
19	Correct	13 ms	12160 KB	Output is correct
20	Correct	12 ms	12160 KB	Output is correct
21	Correct	11 ms	12160 KB	Output is correct
22	Correct	12 ms	12156 KB	Output is correct
23	Correct	11 ms	12160 KB	Output is correct
24	Correct	12 ms	12160 KB	Output is correct
25	Correct	11 ms	12160 KB	Output is correct
26	Correct	12 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	12160 KB	Output is correct
31	Correct	12 ms	12160 KB	Output is correct
32	Correct	17 ms	12160 KB	Output is correct
33	Correct	13 ms	12160 KB	Output is correct
34	Correct	15 ms	12160 KB	Output is correct
35	Correct	12 ms	12160 KB	Output is correct
36	Correct	11 ms	12160 KB	Output is correct
37	Correct	11 ms	12160 KB	Output is correct
38	Correct	11 ms	12160 KB	Output is correct
39	Correct	12 ms	12160 KB	Output is correct
40	Correct	12 ms	12032 KB	Output is correct
41	Correct	11 ms	12140 KB	Output is correct
42	Correct	11 ms	12032 KB	Output is correct
43	Correct	13 ms	12160 KB	Output is correct
44	Correct	12 ms	12160 KB	Output is correct
45	Correct	12 ms	12160 KB	Output is correct
46	Correct	13 ms	12160 KB	Output is correct
47	Correct	12 ms	12160 KB	Output is correct
48	Correct	12 ms	12160 KB	Output is correct
49	Correct	17 ms	12288 KB	Output is correct
50	Correct	11 ms	12032 KB	Output is correct
51	Correct	13 ms	12160 KB	Output is correct
52	Correct	13 ms	12160 KB	Output is correct
53	Correct	12 ms	12160 KB	Output is correct
54	Correct	12 ms	12032 KB	Output is correct
55	Correct	12 ms	12160 KB	Output is correct
56	Correct	12 ms	12160 KB	Output is correct
57	Correct	13 ms	12160 KB	Output is correct
58	Correct	15 ms	12288 KB	Output is correct
59	Correct	432 ms	30060 KB	Output is correct
60	Correct	580 ms	32144 KB	Output is correct
61	Correct	12 ms	12160 KB	Output is correct
62	Correct	12 ms	12160 KB	Output is correct
63	Correct	352 ms	28212 KB	Output is correct
64	Correct	17 ms	12544 KB	Output is correct
65	Correct	24 ms	13696 KB	Output is correct
66	Correct	203 ms	25720 KB	Output is correct
67	Correct	663 ms	40520 KB	Output is correct
68	Correct	680 ms	40956 KB	Output is correct
69	Correct	19 ms	12792 KB	Output is correct
70	Correct	100 ms	19176 KB	Output is correct
71	Correct	333 ms	34968 KB	Output is correct
72	Correct	376 ms	34192 KB	Output is correct
73	Correct	94 ms	17272 KB	Output is correct
74	Correct	459 ms	31104 KB	Output is correct
75	Correct	31 ms	14584 KB	Output is correct
76	Correct	375 ms	34756 KB	Output is correct
77	Correct	300 ms	35184 KB	Output is correct
78	Correct	38 ms	14840 KB	Output is correct
79	Correct	608 ms	38776 KB	Output is correct
80	Correct	17 ms	12288 KB	Output is correct
81	Correct	137 ms	19156 KB	Output is correct
82	Correct	459 ms	33104 KB	Output is correct
83	Correct	510 ms	31076 KB	Output is correct
84	Correct	576 ms	31132 KB	Output is correct
85	Correct	515 ms	31224 KB	Output is correct
86	Correct	437 ms	32064 KB	Output is correct
87	Correct	506 ms	31992 KB	Output is correct

Submission #102148

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