100.IsSameTree.cs

// 100. Same Tree

// Given the roots of two binary trees p and q, 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: p = [1,2,3], q = [1,2,3]
// Output: true
// Example 2:
// Input: p = [1,2], q = [1,null,2]
// Output: false

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     public int val;
 *     public TreeNode left;
 *     public TreeNode right;
 *     public TreeNode(int val=0, TreeNode left=null, TreeNode right=null) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */
public class Solution {
    public bool IsSameTree(TreeNode p, TreeNode q) {
        if(p==null && q==null)
            return true;
        if(p==null || q==null)
            return false;
        if(p.val != q.val)
            return false;
        return IsSameTree(p.left,q.left) && IsSameTree(p.right,q.right);
    }
}

public class Solution {
    public bool IsSameTree(TreeNode p, TreeNode q) {
        if(p == null && q == null)
            return true;
        else if(p == null || q == null)
            return false;
        else if(p.val == q.val)
            return IsSameTree(p.left,q.left) && IsSameTree(p.right,q.right);
        else
            return false;
    }
}