diff --git a/121 Leetcode/114-flatten-binary-tree-to-linked-list.cpp b/121 Leetcode/114-flatten-binary-tree-to-linked-list.cpp
index 88006722..c1983a4e 100644
--- a/121 Leetcode/114-flatten-binary-tree-to-linked-list.cpp	
+++ b/121 Leetcode/114-flatten-binary-tree-to-linked-list.cpp	
@@ -1,18 +1,35 @@
+// class Solution {
+// public:
+// void flatten(TreeNode* root) {
+// if(!root) return;
+// while(root)
+// {
+// TreeNode* temp = root->right;
+// root->right = root->left;
+// // root->left = NULL;
+// TreeNode* node = root;
+// while(node->right)
+// {
+// node = node->right;
+// }
+// node->right = temp;
+// root = root->right;
+// }
+// }
+// };
 class Solution {
 public:
 void flatten(TreeNode* root) {
- if(!root) return;
- while(root)
- {
- TreeNode* temp = root->right;
- root->right = root->left;
- root->left = NULL;
- TreeNode* node = root;
- while(node->right)
- {
- node = node->right;
+ while (root) {
+ if (root->left) {
+ TreeNode* prev = root->left;
+ while (prev->right) {
+ prev = prev->right;
+ }
+ prev->right = root->right;
+ root->right = root->left;
+ root->left = nullptr;
 }
- node->right = temp;
 root = root->right;
 }
 }
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