摘要：
Given a non-empty array containing only positive integers, find if the array can be partitioned into two subsets such that the sum of elements in both 阅读全文
摘要：
Given a 2d grid map of '1's (land) and '0's (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacen 阅读全文
摘要：
Given a positive integer n, find the least number of perfect square numbers (for example, 1, 4, 9, 16, ...) which sum to n. Example 1: Example 2: 阅读全文
摘要：
Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: Integers in each row are sorted i 阅读全文