算法-链表排序（冒泡、选择、插入）

算法-链表排序（冒泡、选择、插⼊）
排序算法
经典排序算法包括：冒泡、选择、和插⼊。

下⾯按照升序排序给出⼀句话解释：
冒泡 -- 进⾏N-1次循环，每次循环从第⼀个元素开始，将此元素和其后元素⽐较，如果前者⼤，则互换位置，直到最后⼀个位置元素被⽐较，执⾏完毕则最⼤的⼀个元素在最后⼀个位置，类似⽔中⽓泡向上冒的过程，越是向上，⽓泡越⼤。

选择 -- 进⾏N-1次循环，每次循环，遍历所有未排序元素，定位最⼤的⼀个元素，将其放到尾部，则最后⼀个位置保证为最⼤元素。

定位的过程就是选择。

插⼊ -- 进⾏N-1次循环，每次循环，取出未排序的第⼀个元素，将此元素插⼊到⼀个新的有序列表中，插⼊过程为从有序列表中第⼀个元素开始，找到第⼀个⼤于待插⼊元素的元素，将待插⼊元素插⼊到此元素前。

数组形式的排序算法例⼦，见下⾯博⽂：
本⽂给出单链表形式的排序代码：
选择排序
/***********************************************************************
selecting sort method
************************************************************************/
// find specific node by strcmpfunc and detach it from list
PT_NODE FindAndDetachNode(PT_NODE ptHeadNode, STRCMPFUNC strcmpfunc )
{
PT_NODE ptTargetNode = NULL;
PT_NODE ptPreMax = NULL;
PT_NODE ptCurNode = NULL;
PT_NODE ptPreNode = NULL;
ptTargetNode = ptHeadNode->next;
ptPreMax = ptHeadNode;
ptCurNode = ptHeadNode->next;
ptPreNode = ptHeadNode;
while( ptCurNode )
{
// current node string is larger than specific node string, record it
if ( strcmpfunc(ptCurNode->str, ptTargetNode->str) )
{
ptTargetNode = ptCurNode;
ptPreMax = ptPreNode;
}
ptPreNode = ptCurNode;
ptCurNode = ptCurNode->next;
}
// specific node found, detach it from list
if ( ptTargetNode )
{
ptPreMax->next = ptTargetNode->next;
ptTargetNode->next = NULL;
}
// sort list by specific order by strcmpfunc
void SortListWithSelectMethod(PT_NODE ptHeadNode, STRCMPFUNC strcmpfunc) {
T_NODE tNewHead = {NULL, NULL};
PT_NODE ptNode = NULL;
// selection sort method
while( TRUE )
{
// find target node and detach it from list
ptNode = FindAndDetachNode(ptHeadNode, strcmpfunc);
if ( !ptNode )
{
break;
}
// insert target node into new list from head
InsertNode2ListHead(&tNewHead, ptNode);
}
// reset head node to new list
ptHeadNode->next = tNewHead.next;
tNewHead.next = NULL;
}
冒泡排序
/***********************************************************************
bubble sort method
************************************************************************/
// bubble list by strcmpfunc and detach last from list
PT_NODE BubbleAndDetachLast(PT_NODE ptHeadNode, STRCMPFUNC strcmpfunc) {
PT_NODE ptCurNode = NULL;
PT_NODE ptPreNode = NULL;
PT_NODE ptNextNode = NULL;
ptCurNode = ptHeadNode->next;
ptPreNode = ptHeadNode;
while( ptCurNode )
{
ptNextNode = ptCurNode->next;
// reach list tail
if ( !ptNextNode )
{
break;
}
// current node string is larger than next node string, swap it
if ( strcmpfunc(ptCurNode->str, ptNextNode->str) )
{
ptPreNode->next = ptNextNode;
ptCurNode->next = ptNextNode->next;
ptNextNode->next = ptCurNode;
// reset current node's previous node
ptPreNode = ptNextNode;
}
else
{
ptPreNode = ptCurNode;
ptCurNode = ptCurNode->next;
}
}
//detach current node from list
ptPreNode->next = NULL;
// current node is the last node, return it
return ptCurNode;
}
// bubble list and detach last from list
ptNode = BubbleAndDetachLast(ptHeadNode, strcmpfunc);
if ( !ptNode )
{
break;
}
// insert max node into new list from head
InsertNode2ListHead(&tNewHead, ptNode);
}
// reset head node to new list
ptHeadNode->next = tNewHead.next;
tNewHead.next = NULL;
}
插⼊排序
/***********************************************************************
inserting sort method
************************************************************************/
PT_NODE DetachFirstNode(PT_NODE ptHeadNode)
{
PT_NODE ptFirstNode = NULL;
ptFirstNode = ptHeadNode->next;
// detach first node from list
if ( ptFirstNode )
{
ptHeadNode->next = ptFirstNode->next;
}
return ptFirstNode;
}
// insert node into list by inserting sort method
void InsertNode2ListByInsertMethod(PT_NODE ptHeadNode, PT_NODE ptNode, STRCMPFUNC strcmpfunc) {
PT_NODE ptPrevNode = NULL;
PT_NODE ptCurNode = NULL;
ptPrevNode = ptHeadNode;
ptCurNode = ptPrevNode->next;
while( ptCurNode )
{
if ( strcmpfunc(ptCurNode->str, ptNode->str) )
{
ptPrevNode->next = ptNode;
ptNode->next = ptCurNode;
// insert ok, let's leave
break;
}
else
{
ptPrevNode = ptCurNode;
ptCurNode = ptCurNode->next;
}
}
// current node is NULL, previous node is last node of list,
// ie, insert not ok, the node shall be added to tail
if ( !ptCurNode )
{
ptPrevNode->next = ptNode;
ptNode->next = NULL;
}
}
// get first node from list
ptNode = DetachFirstNode(ptHeadNode);
if ( !ptNode )
{
break;
}
// insert the node into new list by inserting method
InsertNode2ListByInsertMethod(&tNewHead, ptNode, strcmpfunc); }
// reset head node to new list
ptHeadNode->next = tNewHead.next;
tNewHead.next = NULL;
}。