这种快速排序应该将“v[left]...v[right] 排序为升序”;从 K&R(第二版)的 The C Programming Language 复制(无注释):
void qsort(int v[], int left, int right)
{
int i, last;
void swap(int v[], int i, int j);
if (left >= right)
return;
swap(v, left, (left + right) / 2);
last = left;
for (i = left+1; i <= right; i++)
if (v[i] < v[left])
swap(v, ++last, i);
swap(v, left, last);
qsort(v, left, last-1);
qsort(v, last+1, right);
}
我认为有一个错误
(left + right) / 2
假设左 = INT_MAX - 1,右 = INT_MAX。由于整数溢出,这不会导致未定义的行为吗?