这个快速排序应该将"v [left] ... v [right]排序为增加顺序"; K&R(第二版)从C编程语言中复制(不带注释):
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);
}
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我觉得有一个错误
(left + right) / 2
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假设left = INT_MAX - 1且right = INT_MAX.由于整数溢出,这不会导致未定义的行为吗?