
Leetcode 36 Valid Sudoku
Leetcode 36 Valid Sudoku etermine if a Sudoku is valid, according to: Sudoku Puzzles  The Rules. The Sudoku board could be partially filled, where empty cells are filled with the character '.'. A partially filled sudoku which is valid. Note: A valid Sudoku board (partially filled) is not…

LeetCode 119 Pascal's Triangle II
LeetCode 119 Pascal's Triangle II Given an index k, return the kth row of the Pascal's triangle. For example, given k = 3, Return [1,3,3,1]. Note: Could you optimize your algorithm to use only O(k) extra space? Not a hard question, but if you do not know…

Leetcode 16 3Sum Closest
Leetcode 16 3Sum Closest Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers. You may assume that each input would have exactly one solution. For example, given array S…

TicTacToe
As a chinese, I didn't know this small game has this name before. But this is truly common when you feel boring. Interesting of this game is the simple idea, not too much situation you should consider. This iOS game is based on storyboard, and really simple to implement. Game…

Leetcode 173 Binary Search Tree Iterator
Leetcode 173 Binary Search Tree Iterator Implement an iterator over a binary search tree (BST). Your iterator will be initialized with the root node of a BST. Calling next() will return the next smallest number in the BST. Note: next() and hasNext() should run in average O(1) time and…