Submission #90861

#	Time	Username	Problem	Language	Result	Execution time	Memory
90861		daniel_02	Shymbulak (IZhO14_shymbulak)	C++17	50 / 100	1569 ms	11476 KiB

shymbulak

#include <bits/stdc++.h>

#define fr first
#define pb push_back
#define sc second
#define ll long long

using namespace std;

const int N = 2e5 + 7;
const int inf = 1e6 + 7;

vector<int>g[N];
int d[N];
int cn[N];
queue<pair<int, int>>q;
void mems(){
	for (int i = 0; i < N; i++)
		d[i] = inf;
	queue<pair<int, int>>empty;
	swap(q, empty);
}
void dance(int a)
{
	mems();
	q.push({a, 0});
	d[a] = 0;
	while (!q.empty())
	{
		int v = q.front().fr, cs = q.front().sc;
		q.pop();
		
		if (cs > d[v])continue;
		
		for (int i = 0; i < g[v].size(); i++)
		{
			int to = g[v][i];
			if (cs + 1 <= d[to])
			{
				d[to] = cs + 1;
				cn[d[to]]++;
				q.push({to, d[to]});
			}
		}
	}
}

main()
{
	int n;
	
	cin >> n;
	
	for (int i = 1; i <= n; i++)
	{
		int a, b;
		scanf("%d%d", &a, &b);
		g[a].pb(b);
		g[b].pb(a);
	}
	int mx = 0;
	for (int i = 1; i <= n; i++)
	{
		dance(i);
		for (int j = 1; j <= n; j++)
		{
			if (i == j)continue;
			mx = max(mx, d[j]);
		}
	}
	cout << cn[mx] / 2 << endl;
}

Compilation message (stderr)

shymbulak.cpp: In function 'void dance(int)':
shymbulak.cpp:35:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < g[v].size(); i++)
                   ~~^~~~~~~~~~~~~
shymbulak.cpp: At global scope:
shymbulak.cpp:48:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main()
      ^
shymbulak.cpp: In function 'int main()':
shymbulak.cpp:57:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &a, &b);
   ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 20 / 20
• Subtask 3: 0 / 50