Watch 10 video solutions for Special Positions in a Binary Matrix, a easy level problem involving Array, Matrix. This walkthrough by NeetCodeIO has 34,602 views views. Want to try solving it yourself? Practice on FleetCode or read the detailed text solution.
Given an m x n binary matrix mat, return the number of special positions in mat.
A position (i, j) is called special if mat[i][j] == 1 and all other elements in row i and column j are 0 (rows and columns are 0-indexed).
Example 1:
Input: mat = [[1,0,0],[0,0,1],[1,0,0]] Output: 1 Explanation: (1, 2) is a special position because mat[1][2] == 1 and all other elements in row 1 and column 2 are 0.
Example 2:
Input: mat = [[1,0,0],[0,1,0],[0,0,1]] Output: 3 Explanation: (0, 0), (1, 1) and (2, 2) are special positions.
Constraints:
m == mat.lengthn == mat[i].length1 <= m, n <= 100mat[i][j] is either 0 or 1.