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Submission #24994

# Submission time Handle Problem Language Result Execution time Memory
24994 2017-06-19T17:10:11 Z minimario Network (BOI15_net) C++14
0 / 100
 9 ms 13736 KB 
#include <bits/stdc++.h>

using namespace std;

const int MAX = 500000;
vector<int> g[MAX];
vector<int> order;

void dfs(int u, int p) {
	for (int i : g[u]) {
		if (i == p) { continue; }
		dfs(i, u);
	}
	if (g[u].size() == 1) { order.push_back(u); }
}

int main() {
	/*
	freopen("a.in", "r", stdin);
	freopen("a.out", "w", stdout);
	*/
	int n; scanf("%d", &n);
	for (int i = 0; i < n-1; ++i)
	{
		int u, v; scanf("%d %d", &u, &v);
		u--; v--;
		g[u].push_back(v);
		g[v].push_back(u);
	}
	dfs(0, -1);
	for (int i = 0; i < order.size(); ++i)
	{
		order[i]++;
	}
	printf("%d\n", ((int)order.size()+1)/2);
	for (int i = 0; i < ((int)order.size())/2; ++i) 
	{
		printf("%d %d\n", order[i], order[i+(order.size())/2]);
	}
	if (order.size() % 2 == 1) { printf("%d %d\n", order[0], order[order.back()]); }
}

Compilation message

net.cpp: In function 'int main()':
net.cpp:31:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < order.size(); ++i)
                    ^
net.cpp:22:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  int n; scanf("%d", &n);
                        ^
net.cpp:25:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   int u, v; scanf("%d %d", &u, &v);
                                   ^

Subtask #1
0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 13736 KB Output is correct
2 Correct 0 ms 13736 KB Output is correct
3 Correct 3 ms 13736 KB Output is correct
4 Incorrect 9 ms 13736 KB Integer 0 violates the range [1, 10]
5 Halted 0 ms 0 KB -

Subtask #2
0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 13736 KB Output is correct
2 Correct 0 ms 13736 KB Output is correct
3 Correct 3 ms 13736 KB Output is correct
4 Incorrect 9 ms 13736 KB Integer 0 violates the range [1, 10]
5 Halted 0 ms 0 KB -

Subtask #3
0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 13736 KB Output is correct
2 Correct 0 ms 13736 KB Output is correct
3 Correct 3 ms 13736 KB Output is correct
4 Incorrect 9 ms 13736 KB Integer 0 violates the range [1, 10]
5 Halted 0 ms 0 KB -