1504-count-submatrices-with-all-ones.adoc

1504. Count Submatrices With All Ones

{leetcode}/problems/count-submatrices-with-all-ones/[LeetCode - 1504. Count Submatrices With All Ones ^]

Given an m x n binary matrix mat, return the number of submatrices that have all ones.

Example 1: <img alt="" src="https://assets.leetcode.com/uploads/2021/10/27/ones1-grid.jpg" style="width: 244px; height: 245px;" />

Input: mat = [[1,0,1],[1,1,0],[1,1,0]]
Output: 13
Explanation:
There are 6 rectangles of side 1x1.
There are 2 rectangles of side 1x2.
There are 3 rectangles of side 2x1.
There is 1 rectangle of side 2x2.
There is 1 rectangle of side 3x1.
Total number of rectangles = 6 + 2 + 3 + 1 + 1 = 13.

Example 2: <img alt="" src="https://assets.leetcode.com/uploads/2021/10/27/ones2-grid.jpg" style="width: 324px; height: 245px;" />

Input: mat = [[0,1,1,0],[0,1,1,1],[1,1,1,0]]
Output: 24
Explanation:
There are 8 rectangles of side 1x1.
There are 5 rectangles of side 1x2.
There are 2 rectangles of side 1x3.
There are 4 rectangles of side 2x1.
There are 2 rectangles of side 2x2.
There are 2 rectangles of side 3x1.
There is 1 rectangle of side 3x2.
Total number of rectangles = 8 + 5 + 2 + 4 + 2 + 2 + 1 = 24.

Constraints:

• 1 ⇐ m, n ⇐ 150

• mat[i][j] is either 0 or 1.

思路分析

一刷

link:{sourcedir}/_1504_CountSubmatricesWithAllOnes.java[role=include]

参考资料