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class Solution {
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 public:
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  int computeArea(int ax1, int ay1, int ax2, int ay2, int bx1, int by1, int bx2, int by2) {
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    int rec1 = abs(ax2 - ax1) * abs(ay2 - ay1); // Area(Rectangle 1)
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    int rec2 = abs(bx2 - bx1) * abs(by2 - by1); // Area(Rectangle 2)
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    // As explained above, if intervals overlap, max(x1,x3) < min(x2,x4) and
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    // overlapped interval is ( max(x1,x3) , min(x2,x4) ).
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    int ox1 = (max(ax1, bx1) - min(ax2,
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                                   bx2)); // if ox1 is negative, abs(ox1) is the length of
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                                          // overlapped rectangle, else rectangles do not overlap.
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    int oy1 = (max(ay1, by1) - min(ay2, by2)); // breadth of overlapped
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                                               // rectangle
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    int rec3 = 0;           // if rectangles do not overlap, area of overlapped rectangle
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                            // is zero.
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    if (ox1 < 0 && oy1 < 0) // if both ox1 and oy2 are negative, two rectangles overlap.
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      rec3 = ox1 * oy1;
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    return rec1 + rec2 - rec3; // Area(Rectangle 1) + Area(Rectangle 2) -
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                               // Area(Overlapped triangle)
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  }
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};