Source codes (Java) for leetcode

[DOC]

#Description

Report to solved/unsolved algortithm problems on leetcode.com. Can Also check my blog to see the tricks or pisfall while solving those problems. Do not forget to categorize qustions by their types and chosen algorithms, moreover, analyze its solution, time complexity, approach(iteration/recursion), corner problem, etc.

#Records

• 2020/10/11

  121 Best Time to Buy and Sell Stock

  • 思路
  • 假設 a[i] 為 buy, 則 max{i+1,n} 為 sell 使得 profit 最大

  122 Best Time to Buy and Sell Stock

  • 注意
  • 根据题目的意思，当天卖出以后，当天还可以买入，所以其实可以第三天卖出，第三天买入，第四天又卖出（（5-1）+ （6-5） === 6 - 1）。所以算法可以直接简化为只要今天比昨天大，就卖出。

• 2015/11/04

  #46 permutations

  • memo

    [47 permutation II]

    [46 try iteration solution, and pratice heap sort.]

• 2015/08/11

  valid palindrome

  is palindrome

  Validate Binary Search Tree

  two sum

  search for a range

  palindrome partitioning

  max points of a line

  maximum sub-array

  linked list cycle 2

  letter combinations of a phone number

  combination sum 2

  combination sum 3

  dungeon game

  invert binary tree

  balanced binary tree

  BST iterator

• 2015/07/30

  142 Linked List Cycle II. reference

• 2015/03/23

  [50 Pow(x,n), math, binary search]

  • memo

    [16 3sum Closest, X + Y + Z ~ target]

• 2015/03/15

  [120 Triangle (medium), DP]

  [55 Jump Game (medium), Greedy]

  [78 Subset (medium)]

  [39 Combination Sum (medium)]

  • memo

    [4 Search for a Range (medium)]

    [16 3sum Closest, X + Y + Z ~ target]

    [50 Pow(x,n), math, binary search]

#Comment

• 2015/03/15 From StackOverFlow, it seems not to explicitly initialize the value to announced object, except local variable.