b[small]=b[0]+b[small]; b[0]=b[0]-b[small]; b[small]=b[0]-b[small]; b=b[N-1]+b; b[N-1]=b[N-1]-b; b=b[N-1]-b; /**两个值互换*/
if(a>a[*max]) a[*max]=a; else if (a<a[*min]) a[*min]=a; /**引用传递*/