Same Binary Tree | LeetCode

Given the roots of two binary trees p and q, return true if the trees are equivalent, otherwise return false.

Two binary trees are considered equivalent if they share the exact same structure and the nodes have the same values.

Example 1:

Input: p = [1,2,3], q = [1,2,3]

Output: true

Example 2:

Input: p = [4,7], q = [4,null,7]

Output: false

Example 3:

Input: p = [1,2,3], q = [1,3,2]
Output: false

This algorithm is so intuitive:

1. We initialize a pointer and move it same direction in both the trees
2. if both node doesn't exist it is valid
3. if one exist and another doesn't it is invalid
4. if at any point the value is not equal then it is not the same binary tree

isSameTree(p, q){
 if(!p && !q){
  return true
 }
 if(!p || !q){
  return false
 }
 if(p.val !== q.val){
  return false
 }
 return this.isSameTree(p.left, q.left) &&     
  this.isSameTree(p.right, q.right)
}