leetcode 相同的树

/**

• Definition for a binary tree node.
• public class TreeNode {
• int val;
• TreeNode left;
• TreeNode right;
• TreeNode() {}
• TreeNode(int val) { this.val = val; }
• TreeNode(int val, TreeNode left, TreeNode right) {
• this.val = val;
• this.left = left;
• this.right = right;
• }
• }

*/
class Solution {

public boolean isSameTree(TreeNode p, TreeNode q) {
    //  if two are  empty
    if (p==null&&q==null)
        return true;
    else if (p==null||q==null)
        return false;
    else if (p.val!=q.val)
        return false;
    else {
        return isSameTree(p.left,q.left) &&isSameTree(p.right,q.right);
    }
}

}