Same Tree : Accepted

Author: gouthampradhan

README.md

@@ -269,6 +269,7 @@ My accepted leetcode solutions to some of the common interview problems.
 - [Two Sum IV - Input is a BST](problems/src/tree/TwoSumIV.java) (Easy)
 - [Average of Levels in Binary Tree](problems/src/tree/AverageOfLevelsInBinaryTree.java) (Easy)
 - [Convert Binary Search Tree to Sorted Doubly Linked List](problems/src/tree/BSTtoDoublyLinkedList.java) (Easy)
+- [Same Tree](problems/src/tree/SameTree.java) (Easy)
 
 #### [Two Pointers](problems/src/two_pointers)
 

problems/src/tree/SameTree.java

@@ -0,0 +1,69 @@
+package tree;
+
+/**
+ * Created by gouthamvidyapradhan on 23/01/2018.
+ * Given two binary trees, write a function to check if they are the same or not.
+
+ Two binary trees are considered the same if they are structurally identical and the nodes have the same value.
+
+
+ Example 1:
+
+ Input:     1         1
+ / \       / \
+ 2   3     2   3
+
+ [1,2,3],   [1,2,3]
+
+ Output: true
+ Example 2:
+
+ Input:     1         1
+ /           \
+ 2             2
+
+ [1,2],     [1,null,2]
+
+ Output: false
+ Example 3:
+
+ Input:     1         1
+ / \       / \
+ 2   1     1   2
+
+ [1,2,1],   [1,1,2]
+
+ Output: false
+
+ Solution: Do a pre-order traversal of both the trees in parallel and compare each node
+ */
+public class SameTree {
+
+    public class TreeNode {
+        int val;
+        TreeNode left;
+        TreeNode right;
+        TreeNode(int x) { val = x; }
+    }
+
+    /**
+     * Main method
+     * @param args
+     * @throws Exception
+     */
+    public static void main(String[] args) throws Exception{
+
+    }
+
+    public boolean isSameTree(TreeNode p, TreeNode q) {
+        if((p == null && q != null) || (p != null && q == null)) return false;
+        if(p == null && q == null) return true;
+        else{
+            boolean status = isSameTree(p.left, q.left);
+            if(!status || p.val != q.val){
+                return false;
+            }
+            return isSameTree(p.right, q.right);
+        }
+    }
+}