#include <iostream>
#include <limits.h>
#include <list>
using
namespace
std;
int
x;
void
dfsUtil(
int
node,
int
count,
bool
visited[],
int
& maxCount, list<
int
>* adj)
{
visited[node] =
true
;
count++;
for
(
auto
i = adj[node].begin(); i != adj[node].end(); ++i) {
if
(!visited[*i]) {
if
(count >= maxCount) {
maxCount = count;
x = *i;
}
dfsUtil(*i, count, visited, maxCount, adj);
}
}
}
void
dfs(
int
node,
int
n, list<
int
>* adj,
int
& maxCount)
{
bool
visited[n + 1];
int
count = 0;
for
(
int
i = 1; i <= n; ++i)
visited[i] =
false
;
dfsUtil(node, count + 1, visited, maxCount, adj);
}
int
diameter(list<
int
>* adj,
int
n)
{
int
maxCount = INT_MIN;
dfs(1, n, adj, maxCount);
dfs(x, n, adj, maxCount);
return
maxCount;
}
int
main()
{
int
n = 5;
list<
int
>* adj =
new
list<
int
>[n + 1];
adj[1].push_back(2);
adj[2].push_back(1);
adj[1].push_back(3);
adj[3].push_back(1);
adj[2].push_back(4);
adj[4].push_back(2);
adj[2].push_back(5);
adj[5].push_back(2);
cout <<
"Diameter of the given tree is "
<< diameter(adj, n) << endl;
return
0;
}