leetcode 刷题计划

简单难度

• 0020.Valid Parentheses
• 0026.remove-duplicates-from-sorted-array
• 0053.maximum-sum-subarray 
• 0088.merge-sorted-array
• 0104.maximum-depth-of-binary-tree
• 0121.best-time-to-buy-and-sell-stock
• 0122.best-time-to-buy-and-sell-stock-ii
• 0125.valid-palindrome ?
• 0136.single-number
• 0155.min-stack 
• 0167.two-sum-ii-input-array-is-sorted
• 0169.majority-element
• 0172.factorial-trailing-zeroes
• 0190.reverse-bits
• 0191.number-of-1-bits
• 0198.house-robber
• 0203.remove-linked-list-elements
• 0206.reverse-linked-list
• 0219.contains-duplicate-ii
• 0226.invert-binary-tree
• 0232.implement-queue-using-stacks ?
• 0263.ugly-number
• 0283.move-zeroes
• 0342.power-of-four
• 0349.intersection-of-two-arrays
• 0437.path-sum-iii ?
• 0371.sum-of-two-integers
• 0501.find-mode-in-binary-search-tree?
• 0575.distribute-candies
• 0874.walking-robot-simulation ?
• 1260.shift-2d-grid ?
• 1332.remove-palindromic-subsequences ?