Given a grid where each entry is only 0 or 1, find the number of corner rectangles. A corner rectangle is 4 distinct 1s on the grid that form an axis-aligned rectangle. Note that only the corners need to have the value 1. Also, all four 1s used must be distinct. Example 1: Input: grid = [[1, 0, 0, 1, 0], [0, 0, 1, 0, 1], [0, 0, 0, 1, 0], [1, 0, 1, 0, 1]] Output: 1 Explanation: There is only one corner rectangle, with corners grid[1][2], grid[1][4], grid[3][2], grid[3][4]. Example 2: Input: grid = [[1, 1, 1], [1, 1, 1], [1, 1, 1]] Output: 9 Explanation: There are four 2x2 rectangles, four 2x3 and 3x2 rectangles, and one 3x3 rectangle. Example 3: Input: grid = [[1, 1, 1, 1]] Output: 0 Explanation: Rectangles must have four distinct corners. Note: The number of rows and columns of grid will each be in the range [1, 200]. Each grid[i][j] will be either 0 or 1. The number of 1s in the grid will be at most 6000.