A*

![https://leetcode.com/problems/sliding-puzzle/] On a 2x3 board, there are 5 tiles represented by the integers 1 through 5, and an empty square represented by 0. A move consists of choosing 0 and a 4-directionally adjacent number and swapping it. The state of the board is solved if and only if the board is [[1,2,3],[4,5,0]]. Given a puzzle board, return the least number of moves required so that the state of the board is solved....