novate / brusher

Brush LC!!!

Brusher

Notebooks of Leetcode Brushers! Code brushed in C++|Java|Python now!

• ipynb

Contents

• 1.two-sum - E: py3, C++, Java
• 31.next-permutation - M: py3
• 33.search-in-rotated-sorted-array - M: py3
• 42.trapping-rain-water - H: py3, C++
• 50.powx-n - M: py3
• 56.merge-intervals - M: py3, C++
  • FB Follow-Up: No Sorting
• 67.add-binary - E: py3
• 71.simplify-path - M: py3
• 78.subsets - M: py3
• 124.binary-tree-maximum-path-sum - H: py3
• 139.word-break - M: py3
• 140.word-break-ii - H: py3
• 151.reverse-words-in-a-string - M: py3
• 208.implement-trie-prefix-tree - M: py3
• 199.binary-tree-right-side-view - M: py3
• 215.kth-largest-element-in-an-array - M: py3
• 227.basic-calculator-ii - M: py3
• 236.lowest-common-ancestor-of-a-binary-tree - M: py3
• 314.binary-tree-vertical-order-traversal - M: py3
• 347.top-k-frequent-elements - M: py3
• 370.range-addition - M: py3
  • Range Caching
• 408.valid-word-abbreviation - E: py3
• 415.add-strings - E: py3
• 426.convert-binary-search-tree-to-sorted-doubly-linked-list - M: py3
• 528.random-pick-with-weight - M: py3
• 543.diameter-of-binary-tree - E: py3
  • Bottom Up
  • Follow Up: print the path
• 560.subarray-sum-equals-k - M: py3
• 680.valid-palindrome-ii - E: py3
• 704.binary-search - E: py3
• 912.sort-an-array - M: py3
• 953.verifying-an-alien-dictionary - E: py3, C++
• 987.vertical-order-traversal-of-a-binary-tree - H: py3
• 1249.minimum-remove-to-make-valid-parentheses - M: py3
• 1662.check-if-two-string-arrays-are-equivalent - E: py3

Strategies

• Brush the problems of the same kind together.
• Brush different kind of problems every day. One day, one category.
• Brush each problem at least 3 times:
  • 1st time: check the answer if no ideas in 5 minutes.
  • 2nd time: check the answer if cannot solve independently in 30 minutes.
  • 3rd time: try to solve a problem in 15-20 minutes.
• Always and often check great answers from others in the 75-90 percentile run time.
  • Lower percentile answers might not be of high quality.
  • The most quick answer might contain too much weird tricks that is not universally useful.
• The most important categories are: searching, DP, graph, tree, binary search.
• Practice DP problems as much as you can.
  • It is not guaranteed that you can always successfully find a DP formula each time.
• References:
  • Retag most popular Leetcode problems · GitHub
  • LeetCode 分类+视频对应
  • Google-Facebook-HighFrequence-by Jan3-2020
  • 国内大厂鸡精
  • 国内面试算法笔记
  • 2018 校招总结（外企，国内大公司，国内创业公司）
  • 花花酱 LeetCode 进入千题时代 该如何刷题？1/2 - 刷题找工作 SP15