100. Same Tree--LeetCode Record

Given two binary trees, write a function to check if they are equal or not.

Two binary trees are considered equal if they are structurally identical and the nodes have the same value.

/**
* Definition for a binary tree node.
* public class TreeNode {
*     public var val: Int
*     public var left: TreeNode?
*     public var right: TreeNode?
*     public init(_ val: Int) {
*         self.val = val
*         self.left = nil
*         self.right = nil
*     }
* }
*/
class Solution {
func isSameTree(p: TreeNode?, _ q: TreeNode?) -> Bool {
if p == nil && q == nil {
return true
}else if p == nil || q == nil {
return false
}else if p?.val == q?.val {
return isSameTree(p?.left, q?.left) == true  && isSameTree(p?.right, q?.right) == true
}else {
return false
}
}
}