223. Rectangle Area

Problem Statement

Medium

Given the coordinates of two rectilinear rectangles in a 2D plane, return the total area covered by the two rectangles.

The first rectangle is defined by its bottom-left corner (ax1, ay1) and its top-right corner (ax2, ay2).

The second rectangle is defined by its bottom-left corner (bx1, by1) and its top-right corner (bx2, by2).

Example 1:

Input: ax1 = -3, ay1 = 0, ax2 = 3, ay2 = 4, bx1 = 0, by1 = -1, bx2 = 9, by2 = 2
Output: 45

Example 2:

Input: ax1 = -2, ay1 = -2, ax2 = 2, ay2 = 2, bx1 = -2, by1 = -2, bx2 = 2, by2 = 2
Output: 16

Constraints:

-10⁴ <= ax1 <= ax2 <= 10⁴
-10⁴ <= ay1 <= ay2 <= 10⁴
-10⁴ <= bx1 <= bx2 <= 10⁴
-10⁴ <= by1 <= by2 <= 10⁴

C++

Source file

class Solution {
public:
    int computeArea(int ax1, int ay1, int ax2, int ay2, int bx1, int by1, int bx2, int by2) {
        int cy1 = max(ay1, by1), cx1 = max(ax1, bx1), cy2 = min(ay2, by2), cx2 = min(ax2, bx2);
        // cout << cx1 << cx2 << cy1 << cy2;
        int sumOfAreas = (ax2-ax1)*(ay2-ay1) + (bx2-bx1)*(by2-by1);
        if(bx1>=ax2 || by2<=ay1 || by1>=ay2 || bx2<=ax1)    // disjoint rects
            return sumOfAreas;
        int intersectionArea = (cy2-cy1)*(cx2-cx1);
        return sumOfAreas-intersectionArea;
    }
};