469 - 等价二叉树

3.30 二叉树的题，反正递归是很好用的

至于其他的方法，现在并不想仔细研究。

呵呵

/**
 * 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) {
        if( a == null && b == null){
        	return true;// Write your code here
        }
        if( a != null && b != null){
        	if(a.val == b.val){
        		if(isIdentical(a.left,b.left)){
        			return isIdentical(a.right,b.right);
        		}
        		else
        			return false;
        	}
        }
        return false;
    }
}