oj.uz

답안 #113188

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
113188 2019-05-24T08:22:20 Z davitmarg Network (BOI15_net) C++17
0 / 100
 4 ms 2688 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[100005],start;
vector<int> g[100005];
vector<pair<int, int>> ans, t;

void dfs(int v, int d = 0)
{
	used[v] = 1;
	if (g[v].size() == 1)
	{
		t.PB(MP(d,v));
	}
	for (int i = 0; i < g[v].size(); i++)
	{
		int to = g[v][i];
		if (used[to])
			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);
	sort(all(t));
	if (t.size()%2)
		ans.PB(MP(t[t.size()/2].second, t.back().second));
	for(int i=0;i<t.size()/2;i++)
		ans.PB(MP(t[i].second, t[t.size()-1-i].second));

	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:37:20: 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:77:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<t.size()/2;i++)
              ~^~~~~~~~~~~
net.cpp:81:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < ans.size(); i++)
                  ~~^~~~~~~~~~~~
net.cpp:63:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &a, &b);
   ~~~~~^~~~~~~~~~~~~~~~

Subtask #1
0 / 18.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 2688 KB Output is correct
2 Correct 4 ms 2688 KB Output is correct
3 Correct 3 ms 2688 KB Output is correct
4 Correct 4 ms 2688 KB Output is correct
5 Correct 4 ms 2688 KB Output is correct
6 Correct 4 ms 2688 KB Output is correct
7 Correct 4 ms 2688 KB Output is correct
8 Correct 3 ms 2688 KB Output is correct
9 Correct 3 ms 2688 KB Output is correct
10 Correct 3 ms 2688 KB Output is correct
11 Correct 3 ms 2688 KB Output is correct
12 Correct 3 ms 2688 KB Output is correct
13 Correct 4 ms 2688 KB Output is correct
14 Correct 3 ms 2688 KB Output is correct
15 Correct 4 ms 2688 KB Output is correct
16 Correct 4 ms 2688 KB Output is correct
17 Correct 4 ms 2688 KB Output is correct
18 Incorrect 4 ms 2688 KB Breaking single line is causing network to disconnect.
19 Halted 0 ms 0 KB -

Subtask #2
0 / 45.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 2688 KB Output is correct
2 Correct 4 ms 2688 KB Output is correct
3 Correct 3 ms 2688 KB Output is correct
4 Correct 4 ms 2688 KB Output is correct
5 Correct 4 ms 2688 KB Output is correct
6 Correct 4 ms 2688 KB Output is correct
7 Correct 4 ms 2688 KB Output is correct
8 Correct 3 ms 2688 KB Output is correct
9 Correct 3 ms 2688 KB Output is correct
10 Correct 3 ms 2688 KB Output is correct
11 Correct 3 ms 2688 KB Output is correct
12 Correct 3 ms 2688 KB Output is correct
13 Correct 4 ms 2688 KB Output is correct
14 Correct 3 ms 2688 KB Output is correct
15 Correct 4 ms 2688 KB Output is correct
16 Correct 4 ms 2688 KB Output is correct
17 Correct 4 ms 2688 KB Output is correct
18 Incorrect 4 ms 2688 KB Breaking single line is causing network to disconnect.
19 Halted 0 ms 0 KB -

Subtask #3
0 / 37.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 2688 KB Output is correct
2 Correct 4 ms 2688 KB Output is correct
3 Correct 3 ms 2688 KB Output is correct
4 Correct 4 ms 2688 KB Output is correct
5 Correct 4 ms 2688 KB Output is correct
6 Correct 4 ms 2688 KB Output is correct
7 Correct 4 ms 2688 KB Output is correct
8 Correct 3 ms 2688 KB Output is correct
9 Correct 3 ms 2688 KB Output is correct
10 Correct 3 ms 2688 KB Output is correct
11 Correct 3 ms 2688 KB Output is correct
12 Correct 3 ms 2688 KB Output is correct
13 Correct 4 ms 2688 KB Output is correct
14 Correct 3 ms 2688 KB Output is correct
15 Correct 4 ms 2688 KB Output is correct
16 Correct 4 ms 2688 KB Output is correct
17 Correct 4 ms 2688 KB Output is correct
18 Incorrect 4 ms 2688 KB Breaking single line is causing network to disconnect.
19 Halted 0 ms 0 KB -