Package g0701_0800.s0773_sliding_puzzle

Class Solution

java.lang.Object

g0701_0800.s0773_sliding_puzzle.Solution

public class Solution
extends Object

773 - Sliding Puzzle.

Hard

On an 2 x 3 board, there are five tiles labeled from 1 to 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 the puzzle board board, return the least number of moves required so that the state of the board is solved. If it is impossible for the state of the board to be solved, return -1.

Example 1:

Input: board = [[1,2,3],[4,0,5]]

Output: 1

Explanation: Swap the 0 and the 5 in one move.

Example 2:

Input: board = [[1,2,3],[5,4,0]]

Output: -1

Explanation: No number of moves will make the board solved.

Example 3:

Input: board = [[4,1,2],[5,0,3]]

Output: 5

Explanation:

 5 is the smallest number of moves that solves the board.
 An example path:
 After move 0: [[4,1,2],[5,0,3]]
 After move 1: [[4,1,2],[0,5,3]]
 After move 2: [[0,1,2],[4,5,3]]
 After move 3: [[1,0,2],[4,5,3]]
 After move 4: [[1,2,0],[4,5,3]]
 After move 5: [[1,2,3],[4,5,0]] 

Constraints:

• board.length == 2
• board[i].length == 3
• 0 <= board[i][j] <= 5
• Each value board[i][j] is unique.

Constructor Summary

Constructors

Constructor	Description
Solution()

Method Summary

Modifier and Type	Method	Description
int	slidingPuzzle(int[][] board)
String	swap(String board, int y1, int x1, int y2, int x2)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

slidingPuzzle

public int slidingPuzzle(int[][] board)

swap

public String swap(String board,
                   int y1,
                   int x1,
                   int y2,
                   int x2)