Algorithms

Lintcode and Leetcode

• Linked List
  Reverse a linked list: prev = null, curt = head
  Find the middle point:
  Find the Nth element: remove Nth from END
  Dummy node: when structure could be changed (head modify or delete)

  • AddTwoNumbers

    dummy node,
    int carry = 0;
    carry = sum / 10;
    new ListNode(sum % 10)
    

    • 369 Plus One

       ListNode dummy = new ListNode(0);
       dummy.next = head;
       Stack<ListNode> s = new Stack<>();

  • 148 Sort List

    n log n --> merge sort -> left right -> mid

    • 21 MergeTwoSorted List

  • [206 Reversed Linked list I]

    • 92 Reversed Linked list II

  • 83 RemoveDuplicatesfromSortedList

    • 82 RemoveDuplicatesfromSortedList

      int dupVal = curt.val;

  • 203 Remove Linked List Elements

    if (head.next.val == val)

  • 19 RemoveNthfromEnd

• [Tree]

• [BFS]

• [DFS]