Line of code determines whether two rectangles are intersected

 

typedef struct 
{ 
    int left;
                 // leftmost: leftmost 
    int Top;
                 // TopMost: uppermost 

    int right;
                 // the rightmost: rightmost 
    int bottom;
                 // bottommost: lowermost 

                // actually a combination of two points is expressed conceptual boundary
                 @ are:
                 // left boundary, a right boundary
                 // upper boundary, a lower boundary 
} Rect; 

BOOL isRectOverlap ( const the RECT R1 &, const the RECT & R2) 
{ 
    return !( ((r1.right < r2.left) || (r1.bottom > r2.top)) || 
              ((r2.right < r1.left) || (r2.bottom > r1.top)) 
            )
}

Two rectangles intersect, "the opposite event (" two rectangles do not intersect "is easier to express (case included fewer), the last of the opposite event can be negated:

 

 

 

Two such rectangles are r1 and r2:
the case where both disjoint as: r1 r2 on the left or on the side (Similarly, r1 or r2 on the left upper side), where the structure is necessary to use C concept provided by the industry, i.e. in the rightmost r1 r2 leftmost left, upper side in the minimum r1 r2 is the most.

((r1.right < r2.left) || (r1.bottom > r2.top))
((r2.right < r1.left) || (r2.bottom > r1.top))

Wish us again the meaning of Solutions to this question "opposite event" slightly Description:
opposite event (Complementary event, literally translated as complementary event)
P (Ac) = 1-P (A)
P (Ac) = 1-P (A )

More like often said "either", i.e. the entire sample space (sample space), an event P (A) P (A) and its opposite event P (Ac) P (Ac) , constitute the entire sample space, i.e. in the present embodiment, the sample space is: a combination of two rectangular form on a plane, event: intersection, it is naturally the opposite event: disjoint.
Note that, so as typedef struct rect four variables restriction member, the relationship between the rectangular irregular plane disposed herein can not be solved.

 

 

 

 https://blog.csdn.net/lanchunhui/article/details/50547837