Package 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 java.lang.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
    Description
    Solution()
     

  • Method Summary

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

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • containsCycle

      public boolean containsCycle(char[][] grid)