Count Square Submatrices with All Ones

arraydynamic programmingmatrix

Problem Statement

Given a m * n matrix of ones and zeros, return how many square submatrices have all ones.

Examples

Example 1

Input: matrix =
[
  [0,1,1,1],
  [1,1,1,1],
  [0,1,1,1]
]
Output: 15
There are 10 squares of side 1.
There are 4 squares of side 2.
There is 1 square of side 3.
Total number of squares = 10 + 4 + 1 = 15 .

Example 2

Input: matrix = 
[
 [1,0,1],
 [1,1,0],
 [1,1,0]
]
Output: 7
There are 6 squares of side 1. 
There is 1 square of side 2. 
Total number of squares = 6 + 1 = 7 .

Constraints

1 <= arr.length <= 300

1 <= arr[0].length <= 300

0 <= arr[i][j] <= 1

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Medium

Difficulty

Topic Info

ModuleDSA

CategoryArray

Sub-topicDynamic Programming