Given a 2D list of strings representing a binary matrix of size m x n, where each element is either 0 or 1, compute the area of the largest rectangle containing only 1s. Return the area as an integer.
Example 1
Input: [[1,1,0,1],[1,1,1,1],[0,1,1,1]]
Output: 6
Explanation: The largest rectangle of 1s has area 6.
Example 2
Input: [[0,0],[0,0]]
Output: 0
Explanation: No rectangle of 1s exists.
Example 3
Input: [[1,1],[1,1]]
Output: 4
Explanation: The entire matrix is a rectangle of 1s.
Constraints
Case 1
Input: [['1','0','1','1'],['1','1','1','0'],['1','1','0','0']]
Expected: 4
Case 2
Input: [['0','1','0'],['1','1','1'],['0','1','0']]
Expected: 3
Case 3
Input: [['1']]
Expected: 1
Case 4
Input: [['0']]
Expected: 0
Case 5
Input: [['1','0','1'],['1','1','1'],['1','1','1']]
Expected: 6