100. 相同的树

  1. /**
  2.  * Definition for a binary tree node.
  3.  * public class TreeNode {
  4.  *     int val;
  5.  *     TreeNode left;
  6.  *     TreeNode right;
  7.  *     TreeNode() {}
  8.  *     TreeNode(int val) { this.val = val; }
  9.  *     TreeNode(int val, TreeNode left, TreeNode right) {
  10.  *         this.val = val;
  11.  *         this.left = left;
  12.  *         this.right = right;
  13.  *     }
  14.  * }
  15.  */
  16. class Solution {
  17.     public boolean isSameTree(TreeNode p, TreeNode q) {
  18.         if (p == null && q == null)
  19.             return true;
  20.         else if (p == null || q == null)
  21.             return false;
  22.         else if (p.val != q.val)
  23.             return false;
  24.         else 
  25.             return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);    
  26.     }
  27. }