Package g1901_2000.s1901_find_a_peak_element_ii

Class Solution

java.lang.Object
g1901_2000.s1901_find_a_peak_element_ii.Solution
public class Solution extends java.lang.Object
1901 - Find a Peak Element II.

Medium

A peak element in a 2D grid is an element that is strictly greater than all of its adjacent neighbors to the left, right, top, and bottom.

Given a 0-indexed m x n matrix mat where no two adjacent cells are equal , find any peak element mat[i][j] and return the length 2 array [i,j].

You may assume that the entire matrix is surrounded by an outer perimeter with the value -1 in each cell.

You must write an algorithm that runs in O(m log(n)) or O(n log(m)) time.

Example 1:

Input: mat = [[1,4],[3,2]]

Output: [0,1]

Explanation: Both 3 and 4 are peak elements so [1,0] and [0,1] are both acceptable answers.

Example 2:

Input: mat = [[10,20,15],[21,30,14],[7,16,32]]

Output: [1,1]

Explanation: Both 30 and 32 are peak elements so [1,1] and [2,2] are both acceptable answers.

Constraints:

  • m == mat.length
  • n == mat[i].length
  • 1 <= m, n <= 500
  • 1 <= mat[i][j] <= 105
  • No two adjacent cells are equal.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    int[]
    findPeakGrid(int[][] mat)
     

    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

    • findPeakGrid

      public int[] findPeakGrid(int[][] mat)