Given a 2D matrix matrix , find the sum of the elements inside the rectangle defined by its upper left corner ( row 1, col 1) and lower right corner ( row 2, col 2).
The above rectangle (with the red border) is defined by (row1, col1) =
(2, 1)
and (row2, col2) =
(4, 3)
, which contains sum =
8
.
Example:
Given matrix = [ [3, 0, 1, 4, 2], [5, 6, 3, 2, 1], [1, 2, 0, 1, 5], [4, 1, 0, 1, 7], [1, 0, 3, 0, 5] ] sumRegion(2, 1, 4, 3) -> 8 update(3, 2, 2) sumRegion(2, 1, 4, 3) -> 10
Note: