Compute Two-Rectangle Coverage from Eight Coordinates

### Problem Return the total area covered by two axis-aligned rectangles, counting overlap once. The first is specified by bottom-left `(ax1,ay1)` and top-right `(ax2,ay2)`, and the second by the corresponding b coordinates. ```cpp int computeArea(int ax1, int ay1, int ax2, int ay2, int bx1, int by1, int bx2, int by2); ``` Keep all eight scalar parameters in that order. ### Examples ```text Input: ax1=-2, ay1=-1, ax2=3, ay2=2, bx1=1, by1=0, bx2=5, by2=4 Output: 27 ``` The individual areas are 15 and 16; overlap area is 4. ```text Input: ax1=0, ay1=0, ax2=0, ay2=5, bx1=1, by1=1, bx2=3, by2=4 Output: 6 ``` ### Constraints - Every coordinate is between -10000 and 10000. - Within each rectangle, lower x/y coordinates are at most their corresponding upper coordinates. - Zero-width or zero-height rectangles are allowed by those inequalities.