如何找到在较小矩形的两侧留有最多可用空间的矩形?

如果我正确理解您的问题,这将是一个解决方案(c++),但我没有测试它:

struct Rectangle
{
    size_t x, y;
};

//returns first index which fits your condition
int alg(Rectangle a, Rectangle *others, size_t othersLen)
{
    unsigned int biggestIndex = 0;
    size_t biggest = 0;
    for (int i = 0; i < othersLen; i++)
    {
        size_t diffX = others[i].x - a.x;
        size_t diffY = others[i].y - a.y;
        size_t size = diffX > diffY ? diffY : diffX;
        if (size > biggest)
        {
            biggest = size;
            biggestIndex = i;
        }
    }
    return biggestIndex;
}

编辑:仅当其他矩形大于给定矩形时才起作用,因为它不会产生负差异。