g1501_1600.s1559_detect_cycles_in_2d_grid

Class Solution

java.lang.Object

g1501_1600.s1559_detect_cycles_in_2d_grid.Solution

public class Solution
extends Object

1559 - Detect Cycles in 2D Grid.

Medium

Given a 2D array of characters grid of size m x n, you need to find if there exists any cycle consisting of the same value in grid.

A cycle is a path of length 4 or more in the grid that starts and ends at the same cell. From a given cell, you can move to one of the cells adjacent to it - in one of the four directions (up, down, left, or right), if it has the same value of the current cell.

Also, you cannot move to the cell that you visited in your last move. For example, the cycle (1, 1) -> (1, 2) -> (1, 1) is invalid because from (1, 2) we visited (1, 1) which was the last visited cell.

Return true if any cycle of the same value exists in grid, otherwise, return false.

Example 1:

Input: grid = [[“a”,“a”,“a”,“a”],[“a”,“b”,“b”,“a”],[“a”,“b”,“b”,“a”],[“a”,“a”,“a”,“a”]]

Output: true

Explanation: There are two valid cycles shown in different colors in the image below:

Example 2:

Input: grid = [[“c”,“c”,“c”,“a”],[“c”,“d”,“c”,“c”],[“c”,“c”,“e”,“c”],[“f”,“c”,“c”,“c”]]

Output: true

Explanation: There is only one valid cycle highlighted in the image below:

Example 3:

Input: grid = [[“a”,“b”,“b”],[“b”,“z”,“b”],[“b”,“b”,“a”]]

Output: false

Constraints:

• m == grid.length
• n == grid[i].length
• 1 <= m, n <= 500
• grid consists only of lowercase English letters.

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
boolean	containsCycle(char[][] grid)

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

containsCycle

public boolean containsCycle(char[][] grid)