is Same SubTree Sln

Author: jackzhenguo

Tree/Tree.TreeLib/IsSameTreeSln.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace leetcodeTest
+{
+    public class IsSameTreeSln
+    {
+        // Definition for a binary tree node.
+        public class TreeNode
+        {
+            public int val;
+            public TreeNode left;
+            public TreeNode right;
+            public TreeNode(int x) { val = x; }
+        }
+
+        public bool IsSubtree(TreeNode s, TreeNode t)
+        {
+            if (s == null) return false;
+            if (isSame(s, t)) return true;
+            //s.left-tree和t-tree是不是相等树？
+            //s.right-tree和t-tree是不是相等树？
+            return IsSubtree(s.left, t) || IsSubtree(s.right, t);
+        }
+        //判断s-tree和t-tree是不是相等树
+        private bool isSame(TreeNode s, TreeNode t)
+        {
+            if (s == null && t == null) return true;
+            if (s == null || t == null) return false;
+            return s.val == t.val &&
+                   isSame(s.left, t.left) &&
+                   isSame(s.right, t.right);
+        }
+
+
+    }
+}