使用快速排序对链表进行排序

使用快速排序对链表进行排序

本文代码使用python3语法

 

#链表节点
class Node():
    def __init__(self,val):
        self.val = val
        self.prev = None
        self.next = None

#链表
class LinkedList(object):
    def __init__(self):
        self.head = Node(-1)

    #添加
    def add(self,val):
        temp = Node(val)
        if self.head.next == None:
            print("第一次add")
            self.head.prev = temp
            self.head.next = temp 
            temp.prev = self.head
            temp.next = self.head
        else:
            self._add(temp)

    def _add(self,node:Node):
        #尾插
        temp = self.head.prev  #保留之前的
        temp.next = node
        node.next = self.head
        self.head.prev = node
        node.prev = temp

    #顺序显示
    def show(self):
        p = self.head.next
        while p and  p != self.head:
            print(p.val,end=" ")
            p = p.next
        print()

    #逆序显示
    def reverse(self):
        p = self.head.prev
        while p and p!=self.head:
            print(p.val,end=' ')
            p = p.prev
        print()

    #查找
    def search(self,val):
        if self.head.next == None:
            print("还没有节点")
        else:
            self._search(val)

    def _search(self,val):
        p = self.head.next
        while p != self.head:
            if p.val == val:
                return p
            p = p.next
        return None

    #删除
    def delete(self,val):
        if self.head.next == None:
            print("还没有节点")
        else:
            node = self._search(val)
            if not node:
                return 0
            prev_ = node.prev
            next_ = node.next
            prev_ .next = next_
            next_.prev = prev_
            del(node)

    #删第一个元素
    def popleft(self):
        if self.head.next == None:
            print("还没有节点")
        else:
            temp = self.head.next
            self.head.next = temp.next
            temp.next.prev = self.head
            return temp

    #删除最后一个元素
    def popright(self):
        if self.head.next == None:
            print("还没有节点")
        else:
            temp = self.head.prev
            self.head.prev = temp.prev
            temp.prev.next = self.head
            



    #插入
    def insert(self,index,val):
        if self.head.next == None:
            print("还没有节点")
        else:
            temp = Node(val)
            p = self.head.next
            while index:
                p = p.next
                index -= 1

            prev_ = p.prev
            prev_.next = temp
            temp.next = p
            p.prev = temp
            temp.prev = prev_

    def sort(self):
        if self.head.next == None:
            return
        else:
            self._sort(self.head.next,self.head.prev)

    def inRight(self,base,target,scope):
        #判断target是否在base节点的后面n,scope表示此次比较的范围,即[base,scope]
        p = base.next
        while p != scope.next:
            if p == target:
                return True
            p = p.next
        return False


    def _sort(self,left,right):
        #快排
        if self.inRight(left,right,self.head):
            base_val = left.val
            l,r = left,right
            while self.inRight(l,r,right):
                while self.inRight(l,r,right) and  r.val >= base_val:
                    r = r.prev
                if self.inRight(l,r,right):
                    l.val = r.val
                    l = l.next

                while self.inRight(l,r,right) and l.val < base_val:
                    l = l.next
                if self.inRight(l,r,right):
                    r.val = l.val
                    r = r.prev
            l.val = base_val
            self._sort(left,l)
            self._sort(l.next,right)


if __name__ == "__main__":
    a = LinkedList()
    a.add(10)
    a.add(2)
    a.add(3)
    a.add(14)
    a.add(15)
    a.add(5)
    a.add(5)
    a.add(8)
    a.add(9)
    a.add(11)
    a.add(12)

    print("sort before:")
    a.show()

    a.sort()
    print("sort after:")
    a.show()

 

sort before:
10 2 3 14 15 5 5 8 9 11 12
sort after:
2 3 5 5 8 9 1011 12 14 15