leetcode-105 - Construct Binary Tree from Preorder and Inorder Traversal
動機 複習inorder與preorder 可以順便看106 ...
Hash Table
leetcode-560 - Subarray Sum Equals K
動機 我忘了prefix sum!! 同時，這題不能用sliding window ...
leetcode-347 - Top K Frequent Elements
動機 直接sort就好 ...
leetcode-387 - First Unique Character in a String
動機 複習Counter ...
leetcode-349 - Intersection of Two Arrays
動機 iteratable可以轉成set ...
leetcode-142 - Linked List Cycle II
動機 複習判圈與找loop起點 ...
leetcode-3 - Longest Substring Without Repeating Characters
動機 複習sliding windows ...
leetcode-141 - Linked List Cycle
動機 複習判圈 ...
leetcode-1 - Two Sum
動機 lambda加map好方便 ...
leetcode-395 - Longest Substring with At Least K Repeating Characters
動機 搞懂調整sliding window的條件 ...