solved: 652. Find Duplicate Subtrees

Signed-off-by: rajput-hemant <rajput.hemant2001@gmail.com>

Author: rajput-hemant

src/0601-0700/652 - Find Duplicate Subtrees/find_duplicate_subtrees.go

@@ -0,0 +1,40 @@
+package main
+
+import "strconv"
+
+// Definition for a binary tree node.
+type TreeNode struct {
+	Val   int
+	Left  *TreeNode
+	Right *TreeNode
+}
+
+func findDuplicateSubtrees(root *TreeNode) []*TreeNode {
+	// to store the hash value of subtrees
+	hashMap := make(map[string]int)
+	// to store the result
+	res := make([]*TreeNode, 0)
+	// traverse the tree
+	traverse(root, hashMap, &res)
+	return res
+}
+
+// traverse the tree
+func traverse(root *TreeNode, hashMap map[string]int, res *[]*TreeNode) string {
+	// if the root is nil, return "#"
+	if root == nil {
+		return "#"
+	}
+	// traverse the left and right subtree
+	left := traverse(root.Left, hashMap, res)
+	right := traverse(root.Right, hashMap, res)
+	// get the hash value of the subtree
+	subTree := left + "," + right + "," + strconv.Itoa(root.Val)
+	// if the hash value of the subtree is 1, it means that the subtree is duplicated
+	if hashMap[subTree] == 1 {
+		*res = append(*res, root)
+	}
+	// add the hash value of the subtree to the hashMap
+	hashMap[subTree]++
+	return subTree
+}