#3212

Count Submatrices With Equal Frequency of X and Y

medium · 51.5% accepted · 161 likes · top 41%

array · matrix · prefix sum

⊣ practice⊣ open on leetcode ↗

Description

Given a 2D character matrix grid, where grid[i][j] is either 'X', 'Y', or '.', return the number of submatrices that contain:

 - grid[0][0]

 - an equal frequency of 'X' and 'Y'.

 - at least one 'X'.

Solution