Submission #317861

#	Time	Username	Problem	Language	Result	Execution time	Memory
317861		Kesatria_Komodo	Network (BOI15_net)	C++17	0 / 100	8 ms	12032 KiB

net

#include <cstdio>
#include <vector>
std::vector<int> leaf , adjlist[500001];
void dfs(int node , int par){
    for (int it : adjlist[node])
        if (it != par)
            dfs(it , node);
    if (adjlist[node].size() == 1)
        leaf.push_back(node);
}
int main(){
    int n;
    scanf("%d" , &n);
    for (int i = 1 ; i < n ; i++){
        int a , b;
        scanf("%d%d" , &a , &b);
        adjlist[a].push_back(b);
        adjlist[b].push_back(a);
    }
    for (int i = 1 ; i <= n ; i++)
        if (adjlist[i].size() > 1){
            dfs(i , i);
            break;
        }
    printf("%u\n" , leaf.size() / 2 + leaf.size() % 2);
    for (int i = 1 ; i < leaf.size() ; i += 2)
        printf("%d %d\n" , leaf[i] , leaf[i - 1]);
    if (leaf.size() & 1)
        printf("%d %d\n" , leaf[leaf.size() - 1] , leaf[leaf.size() - 2]);
}

Compilation message (stderr)

net.cpp: In function 'int main()':
net.cpp:25:14: warning: format '%u' expects argument of type 'unsigned int', but argument 2 has type 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wformat=]
   25 |     printf("%u\n" , leaf.size() / 2 + leaf.size() % 2);
      |             ~^      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      |              |                      |
      |              unsigned int           std::vector<int>::size_type {aka long unsigned int}
      |             %lu
net.cpp:26:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   26 |     for (int i = 1 ; i < leaf.size() ; i += 2)
      |                      ~~^~~~~~~~~~~~~
net.cpp:13:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   13 |     scanf("%d" , &n);
      |     ~~~~~^~~~~~~~~~~
net.cpp:16:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   16 |         scanf("%d%d" , &a , &b);
      |         ~~~~~^~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 18
• Subtask 2: 0 / 45
• Subtask 3: 0 / 37