141

Author: Alimov-8

Data Structure 1/141. Linked List Cycle.md

@@ -0,0 +1,28 @@
+# Leetcode 141. Linked List Cycle
+
+
+## HashTable and Loop
+```py
+
+# Definition for singly-linked list.
+# class ListNode:
+#     def __init__(self, x):
+#         self.val = x
+#         self.next = None
+
+class Solution:
+    def hasCycle(self, head: Optional[ListNode]) -> bool:
+        d = {}
+        
+        while(True):
+            if head is None:
+                return False
+            
+            if head.next in d.keys():
+                if head.val == d[head.next]:
+                    return True
+            
+            d[head.next] = head.val
+            head = head.next          
+       
+```

Data Structure 1/21. Merge Two Sorted Lists.md

@@ -0,0 +1,13 @@
+# Leetcode 21. Merge Two Sorted Lists
+
+
+## LinkedList Looping
+```py
+# Time Complexity - 
+       
+```
+
+            
+            
+                
+        

Data Structure 1/README.md

@@ -1,28 +1,31 @@
 # LeetCode Study Plan 📋 | [Data Structures 1](https://leetcode.com/study-plan/data-structure/)
 
 ## Solutions 
-Array
+
 - [1. Two Sum - Brute Force and Dictionary](https://github.com/Alimov-8/leetcode-solutions/blob/master/Data%20Structure%201/1.%20Two%20Sum.md#leetcode-1-two-sum)
 
-- [36. Valid Sudoku](https://github.com/Alimov-8/leetcode-solutions/blob/master/Data%20Structure%201/36.%20Valid%20Sudoku.md#list-comprehensions-sets-count)
+- [36. Valid Sudoku - Array](https://github.com/Alimov-8/leetcode-solutions/blob/master/Data%20Structure%201/36.%20Valid%20Sudoku.md#list-comprehensions-sets-count)
 
 - [53. Max Sub Array - Kadane's Algorithm](https://github.com/Alimov-8/leetcode-solutions/blob/master/Data%20Structure%201/53.%20Maximum%20Subarray.md#leetcode-53-max-sub-array)
 
 - [83. Remove Duplicates from Sorted List - Recursion](https://github.com/Alimov-8/leetcode-solutions/blob/master/Data%20Structure%201/)
 
 - [88. Merge Sorted Array - Two Pointers, Compersion Sorting](https://github.com/Alimov-8/leetcode-solutions/blob/master/Data%20Structure%201/88.%20Merge%20Sorted%20Array.md#leetcode-88-merge-sorted-array)
 
-- [118. Pascal's Triangle](https://github.com/Alimov-8/leetcode-solutions/blob/master/Data%20Structure%201/118.%20Pascal's%20Triangle.md#leetcode-118-pascals-triangle)
+- [118. Pascal's Triangle - Array](https://github.com/Alimov-8/leetcode-solutions/blob/master/Data%20Structure%201/118.%20Pascal's%20Triangle.md#leetcode-118-pascals-triangle)
 
 - [121. Best Time to Buy and Sell Stock](https://github.com/Alimov-8/leetcode-solutions/blob/master/Data%20Structure%201/121.%20Best%20Time%20to%20Buy%20and%20Sell%20Stock.md#leetcode-121-best-time-to-buy-and-sell-stock)
 
+- [141. Linked List Cycle - Hashmap, Loop](https://github.com/Alimov-8/leetcode-solutions/blob/master/Data%20Structure%201/)
+
+
 - [206. Reverse the LinkedList - Recursion](https://github.com/Alimov-8/leetcode-solutions/blob/master/Data%20Structure%201/)
 
 - [217. Contains Duplication - Dictionary](https://github.com/Alimov-8/leetcode-solutions/blob/master/Data%20Structure%201/217.%20Contains%20Duplicate.md#leetcode-217-contains-duplication)
 
 - [350. Intersection of Two Arrays II - Dictionary, Loops](https://github.com/Alimov-8/leetcode-solutions/blob/master/Data%20Structure%201/217.%20Contains%20Duplicate.md#leetcode-350-intersection-of-two-array-ii)
 
-- [383. Ransom Note](https://github.com/Alimov-8/leetcode-solutions/blob/master/Data%20Structure%201/383.%20Ransom%20Note.md)
+- [383. Ransom Note - HashMap, Counting](https://github.com/Alimov-8/leetcode-solutions/blob/master/Data%20Structure%201/383.%20Ransom%20Note.md)
 
 - [387. First Unique Character in a String](https://github.com/Alimov-8/leetcode-solutions/blob/master/Data%20Structure%201/387.%20First%20Unique%20Character%20in%20a%20String.md#leetcode-387-first-unique-character-in-a-string)