1277. Count Square Submatrices with All Ones

https://leetcode.com/problems/count-square-submatrices-with-all-ones

Description

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

Example 1:

**Input:** matrix =
[
  [0,1,1,1],
  [1,1,1,1],
  [0,1,1,1]
]
**Output:** 15
**Explanation:** 
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
**Explanation:** 
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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