100. Same Tree

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Given two binary trees, write a function to check if they are the same or not.
Two binary trees are considered the same if they are structurally identical and the nodes have the same value.
Example 1:
Input:     1         1
          / \       / \
         2   3     2   3

        [1,2,3],   [1,2,3]

Output: true
Example 2:
Input:     1         1
          /           \
         2             2

        [1,2],     [1,null,2]

Output: false
Example 3:
Input:     1         1
          / \       / \
         2   1     1   2

        [1,2,1],   [1,1,2]

Output: false
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Intuition

 Start with root node
If both are null - true
If one is null other non null - false
If value is different - false
Recurse into corresponding left, and right nodes

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Time - O(n)
Space - O(h)