Problem53 - find max sub-array inside array
Problem54 - spiral matrix
Problem55 - jump solution
Problem73 - path simplification
Problem121 - find max order
NumberOfIslands - 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 adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by water.
Solution is implemented using FIFO queue.