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督促自己，目标每天打卡五道题，加上看书一小时

516 Longest Palindromic Subsequence
     - dp bottom up,  
     - if s.charAt(i) == s.charAt(j) dp[i][j] == dp[i + 1][j - 1] + 2
     - else dp[i][j] = max(dp[i + 1][j], dp[i][j - 1])
     - when coding, start from last line of array and make the first value dp[i][i] = 1 first.
728. Self Dividing Numbers
    - how to iterate over all digits of a number
    - String.valueOf(n).toCharArray()
740. Delete and Earn
    - similar to house rober
    - use taken/notaken to track state of last index
    - taken = notaken + track[i]
    - notaken = max(taken, nonTaken)

896 Monotonic Array
    - use a flag to check status
650 2 Keys Keyboard
     - for prime number at least n operations
     - get the largest divisor and its operations
696 Count Binary Substrings
     - get the number of each group
     - the idea of groups is pretty tricky
835 Image Overlap
     - get the movement of overlapping each pair of 1
     - count the number of all movements and the max is the result
732 My Calendar III
     - represent timeline using a treemap, key is time, value is add/remove events at this time

287 Find the Duplicate Number
     - if number 1 has showed, change the number at index 1 to -1. Use -x to mark existing ones.
297 Serialize and Deserialize Binary Tree
    - BFS for generating string representation
    - use a queue for deserialize, every time deal with two nodes
718 Maximum Length of Repeated Subarray
    - dp and dp[i][j] represents matching number of substrings start at i and j
    - bottom up dp and corner cases
781 Rabbits in Forest
     - using hashmap for grouping rabbits
885 Spiral Matrix III
     - find the pattern

87 Scramble String
      - recursive
575 Distribute Candies
538 Convert BST to Greater Tree
      - recursive/iterative reverse inorder traversal
457 Circular Array Loop
      - slow/fast pointer to check if there is a loop
321 Create Maximum Number
       - how to get size k of original ordered number from an array

402 Remove K Digits
    - stack and greedy
    - how to make decisions at different situations
819 Most Common Word
     - cut a sentence into words
     - String[] words = input.toLowerCase().replaceAll("[^\\w\\s]", " ").split(""\\s+);
今天有哥们毕业回国了，喝了一顿

843 Guess the Word
    - how to use current guess to eliminate the domain to search
401 Binary Watch
    - dfs for generating possible combinations
97 Interleaving String
   - dp state transfer function (how to get to this state from previous know state)
133 Clone Graph
   - bfs to clone node and edge at the same time
924 Minimize Malware Spread
    - dfs for coloring nodes of different groups
   

楼主，这几天咋不来了？

love1point 发表于 2018-12-25 09:02
楼主，这几天咋不来了？

这两天圣诞节，有朋友过来玩，就三天打鱼两天晒网了。明天开始洗心革面hhhh，谢谢关心~

606 Construct String from Binary Tree
      - recursive preorder traversal
497 Random Point in Non-overlapping Rectangles
      - represent different possibility using a treemap and ceilingKey
177 Nth Highest Salary
     - limit and offset
530 Minimum Absolute Difference in BST
    - iterative in order traversal of a BST with a stack
873 Length of Longest Fibonacci Subsequence
    - set for checking existence and search for each two start pari

楼主也是在职跳槽么？一起加油呀

Fieudi 发表于 2018-12-28 10:22
楼主也是在职跳槽么？一起加油呀

不是哎，刚毕业~~ 一起加油哇