Get the sum of area of two rectangles.

TwoRectanglesArea.java

/**
 * Created by Kwangshin on 2015-09-17.
 * Email : kwangshin@gmail.com
 */
public class TwoRectanglesArea {
    public int getAreaOfTwoRectangles(int K, int L, int M, int N, int P, int Q, int R, int S) {
        // Get the sum of area of two rectangles separately, i.e., no concern about the overlapped area.
        long twoRectanglesAreaSeparately = this.getTwoRectanglesAreaSeparately(K, L, M, N, P, Q, R, S);

        // Overlapping area right is the smaller value in two rectangles right values.
        int overlappingAreaRight = (R < M) ? R : M;
        // Overlapping area left is the bigger value in two rectangles left values.
        int overlappingAreaLeft = (K < P) ? P : K;
        // Get overlapping area width...
        int overlappingAreaWidth = overlappingAreaRight - overlappingAreaLeft;

        if(overlappingAreaWidth <= 0) {
            // Two rectangles are not overlapped.
            return twoRectanglesAreaSeparately > 2147483647 ? -1 : (int) twoRectanglesAreaSeparately;
        }

        // Overlapping area top is the smaller value in two rectangles top values.
        int overlappingAreaTop = (N < S) ? N : S;
        // Overlapping area bottom is the bigger value in two rectangles bottom values.
        int overlappingAreaBottom = (L < Q) ? Q : L;
        // Get overlapping area height...
        int overlappingAreaHeight = overlappingAreaTop - overlappingAreaBottom;

        if(overlappingAreaHeight <= 0) {
            // Two rectangles are not overlapped.
            return twoRectanglesAreaSeparately > 2147483647 ? -1 : (int) twoRectanglesAreaSeparately;
        }

        // Two rectangles have the overlapped area.
        long overlappedRectangleArea = overlappingAreaWidth * overlappingAreaHeight;

        long areaOfSumOfRectangles = twoRectanglesAreaSeparately - overlappedRectangleArea;

        return areaOfSumOfRectangles > 2147483647 ? -1 : (int) areaOfSumOfRectangles;
    }

    private long getTwoRectanglesAreaSeparately(int K, int L, int M, int N, int P, int Q, int R, int S) {
        // The area of first rectangle.
        int firstRectangleWidth = M-K;
        int firstRectangleHeight = N-L;
        long firstRectangleArea = firstRectangleWidth * firstRectangleHeight;

        // The area of second rectangle.
        int secondRectangleWidth = R-P;
        int secondRectangleHeight = S-Q;
        long secondRectangleArea = secondRectangleWidth * secondRectangleHeight;

        long sumOfTwoRectanglesSeparately = firstRectangleArea + secondRectangleArea;

        return sumOfTwoRectanglesSeparately;
    }
}