_notes.yaml

Review:

  _leet:
      medium1:
        clone-graph.py
        decode-ways.py
        find-peak-element.py  - eff *
        longestIncreasingSubsequence.py   *
        maximum-product-subarray.py(eff)   *
        minimum-time-difference.py
          perfect_square_sums.py      TODO
        permutations-of-string-list-backtrack.py
        string_compression.py   **
          task-scheduler.py     TODO

      medium2:
        jump-game.py
            k-closest-points-to-origin.py   TODO
        least-number-of-unique-integers-after-k-removals.py   *
            matrix-block-sum.py     TODO
        minimum-path-sum-triangle.py
        next-permutation.py
        number-of-connected-components-in-an-undirected-graph.py
        remove-duplicate-letters.py
        shortest-bridge-dfs-bfs.py  **
        shortest-unsorted-continuous-subarray.py
        spiral-matrix-ii.py
        valid-sudoku.py

      medium3:
        angle-between-hands-of-a-clock.py
        climbing-stairs.py
        combinations-of-phone-num_backtrack.py
        count-binary-substrings.py    *
        longest-substring-k-distinct-char.py    **
        min-num-frogs-croaking.py   *
        restore-ip-addresses_backtrack.py     **    TODO
        simplify-path.py
        valid-parenthesis-string.py   **

      medium4-easy:
        add-binary.py
        add-strings.py
        find-common-characters.py
        pascals-triangle.py

      medium5-easy:
        happy-number.py
        subdomain-visit-count.py
        two-sum.py
          verifying-an-alien-dictionary.py    TODO

      medium6:
        3Sum.py
        merge-sorted-array.py
          minimum-cost-to-hire-work.py    TODO
        minimum-window-substring.py   **
        split-array-k-sub-array-max-sum.py  **
        word-square.py    **
      
      design:
        binary-search-tree-iterator.py
        design-file-system.py
        hit-counter.py
        log-storage-system.py
        shortest-word-distance.py
        twitter.py
        words-data-structure.py
        zigzag-iterator.py



  2-dim:
    https://www.geeksforgeeks.org/print-all-possible-paths-from-top-left-to-bottom-right-of-a-mxn-matrix/
    find-islands-maxarea.py
    flood-fill-algorithm.py
    possible-paths-top-left-bottom-right-nxm-matrix.py
    leet:
      maximal_square.py
        n-queens.py   TODO
      number-of-provinces.py
      RemoveStones.py
        snakes-and-ladders.py    TODO
      word-search-board.py



  Array:
    2-count-duplets-key-pair-difference.py
    2-pythagorean-triplet-in-an-unsorted-array.py
    4-max-sum-cont-subarray-kadane - greedy
      4-max-sum-without-adjacents.py  **  TODO
    4-subarray-sums-divisible-by-k - eff  *
    4-subarray-with-given-sum
    find-minimum-difference-pair.py
    minimum-meeting_rooms
    rearrange-array-into-zig-zag-fashion.py
    reorganize-string-alternatively   **
      https://leetcode.com/problems/trapping-rain-water-ii/   TODO



  String:
    1-longest-substring-count-without-repeating-char.py      *
    2-longestpalindrome.py      *
    2-palindrome-partitioning.py  **
    2-palindrome-substring.py     *
    colNameForNumberExcel.py
    implement-strstr.py   **
    permutations-of-a-given-string-backtracking.py
    remove-minimum-number-characters-two-strings-become-anagram-2.py
    word-break.py


 
  Tree:
    bst-validate.py
    BT-diameter.py
    BT-duplicate-subtrees.py
    BT-Lowest_common_ancestor.py
    BT-MinDepth.py   **
    BT-Path-root-to-leaf-Sum.py
    BT-Path-root-to-leaf.py
    connect-nodes-at-same-level.py    TODO
    invert-binary-tree.py
    merge-two-bt-sum.py
    tree-traversal-build-preorder.py   TODO



  LinkedList:
    2-DoubleLinkedList.py
    addTwoNumbers-linkedlist.py
    partition-linked-list.py  *
    remove-linked-list-elements.py  *
    reorder-list-alternatively.py   *
    sort-linked-list.py    **



  DataStructures:
      min-heap.py
      max-stack.py



Concepts:
  Balance string:
    stack, index to remove, left+-, right+-, balance+-

  Backtrack:
    _leet:
      medium1/balanced_paranthesis_generate_backtrack.py  <for i in range(start, len(input))>
      medium1/permutations-of-string-list-backtrack.py
      medium3/combinations-of-phone-num_backtrack.py
      medium3/restore-ip-addresses_backtrack.py   *
      _leet/medium6/coin_change.py

  DFS:
    _leet:
      medium1/course-schedule.py    *
      medium2/shortest-bridge-dfs-bfs.py    *

  Dynamic:
    _leet:
      medium1/decode-ways.py
      medium1/longestIncreasingSubsequence.py
      medium3/climbing-stairs-min-cost.py
      medium3/climbing-stairs.py

  string:
    map and filter _leet/array/valid-palindrome.py 

  FileSystem:
    _leet/design/design-file-system.py
    _leet/design/words-data-structure.py
    2-Dim/leet/word-search-board.py

  lambda sort:
    _leet/medium1/top-k-frequent-elements.py
    _leet/medium1/mergeIntervals.py
    _leet/medium3/reorder-data-in-log-files.py
    _leet/medium1/minimum-time-difference.py
    Array/arrange-largest-number.py

  minimum window:
    _leet/medium6/minimum-window-substring.py

Tricks:
  Array:
    l=0,r=1
    l=0,r=n-1

    seen={} - to check if we already computed this value
    enumerate - to keep track of index of array and its value

    Counter() - gives dict of element as key, and how many times it repeated as value

    for i in range(n-1,2,-1) - reverese order from n-1th element to 2nd element

    helper function for sort - arrange-largest-number


  String:
    sliding window  String/0.1-longest-substring-without-repeating-characters.py

  dictionary:
    set default value: 2-Dim/leet/word-search-board.py
      trie = {}

  sort:
    bisect, bisect.insort,  
      i = bisect.bisect_left(<list>, 3) returns index wher 3 can be inserted
      _leet/design/Leaderboard.py
    heapq.heappush (useful when we have tuples to sort) - example _leet/design/twitter.py 

  for loops:
    _leet/medium4-easy/find-common-characters.py

TODO:
  python



Reviewd:
  _leet
  2_dim
  Tree
  linkedlist