lintcode-easy-Identical Binary Tree

Check if two binary trees are identical. Identical means the two binary trees have the same structure and every identical position has the same value.

 Identical Binary TreeShow result 

 

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Check if two binary trees are identical. Identical means the two binary trees have the same structure and every identical position has the same value.

Have you met this question in a real interview? 

Yes

Example

    1             1
   / \           / \
  2   2   and   2   2
 /             /
4             4

are identical.

    1             1
   / \           / \
  2   3   and   2   3
 /               \
4                 4

are not identical.

递归一下就可以了

/**
 * Definition of TreeNode:
 * public class TreeNode {
 *     public int val;
 *     public TreeNode left, right;
 *     public TreeNode(int val) {
 *         this.val = val;
 *         this.left = this.right = null;
 *     }
 * }
 */
public class Solution {
    /**
     * @param a, b, the root of binary trees.
     * @return true if they are identical, or false.
     */
    public boolean isIdentical(TreeNode a, TreeNode b) {
        // Write your code here
        if(a == null && b == null)
            return true;
        if(a == null || b == null)
            return false;
        if(a.val != b.val)
            return false;
        
        return isIdentical(a.left, b.left) && isIdentical(a.right, b.right);
    }
}