Watch 10 video solutions for Count Submatrices With Equal Frequency of X and Y, a medium level problem involving Array, Matrix, Prefix Sum. This walkthrough by Fraz has 30,539 views views. Want to try solving it yourself? Practice on FleetCode or read the detailed text solution.
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]'X' and 'Y'.'X'.
Example 1:
Input: grid = [["X","Y","."],["Y",".","."]]
Output: 3
Explanation:
Example 2:
Input: grid = [["X","X"],["X","Y"]]
Output: 0
Explanation:
No submatrix has an equal frequency of 'X' and 'Y'.
Example 3:
Input: grid = [[".","."],[".","."]]
Output: 0
Explanation:
No submatrix has at least one 'X'.
Constraints:
1 <= grid.length, grid[i].length <= 1000grid[i][j] is either 'X', 'Y', or '.'.