a trick for recursive problems

#coding #leetcode #python

[TECHADVICETEAM]

Still waiting for the trick part in the video

[ChiragSharma-pbrg]

Like we can do it by first of all calculate height of binary tree by taking r=height(root.right) and l=height(root.left) and and return Math.max(l, h)+1 and create basic cases like if root is null then no return for diameter and make 3 variables d1=diameter (root.left) d2=diameter (root.right) and and finally return Math.max(Math.max(d1, d2), d3) and finally we got diameter of BT

[a.m.]

You can also write a simple traditional bfs first. Then just call that on root.left and root.right separately on their own.

[CAMOBAP]

Why update self.res inside dfs and use return value form first dfs call?

[king]

This is so much worse in C++ 💀. I should switch to python

[mystikyogi]

Why are we returning max in dfs function = 1 + max (left, right)?