[leetcode question brushing record] sorting

Completed
121-130

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1. data structure

Hashtable

LeetCode 128. The longest continuous sequence

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2. Commonly used algorithm

Search for

Flood Fill

LeetCode 130. The surrounding area

recursive

LeetCode 129. Root to the sum of the leaf node numbers

Double pointer

LeetCode 125. Verify the palindrome string

greedy

LeetCode 121. The best time to buy and sell stocks
LeetCode 122. The best time to buy and sell stocks II

Infix decomposition

LeetCode 123. The best time to buy and sell stocks III

3. Dynamic programming

Tree form DP

LeetCode 124. The maximum path in a binary tree and

4. graph theory

LeetCode 126. The word chain II
LeetCode 127. The word chain