How to find nodes in a tree which has longest path?

Question

      40
      /\
     20 60
     /\  \
   10 30  80
      /   /\
     25  70 90
           \
           75

longest path 
25 30 20 40 60 80 70 75 
Answer
    25 ----> 75

Answer 1

Check this but will not tell the nodes only the length of the path...

int maxDepth(Node root) {
    if(root == null) {
        return 0;
    } else {
        int ldepth = maxDepth(root.left);
        int rdepth = maxDepth(root.right);
        return ldepth>rdepth ? ldepth+1 : rdepth+1;
    }
}

int longestPath(Node root)
{
   if (root == null)
     return 0;

  int ldepth = maxDepth(root.left);
  int rdepth = maxDepth(root.right);

  int lLongPath = longestPath(root.left);
  int rLongPath = longestPath(root.right);

  return max(ldepth + rdepth + 1, max(lLongPath, rLongPath));
}

Comments

use floyd warshall's algo after mapping the tree in a matrix. Then calculate the maximum distance.