Python之链表

class Node(object):
    def __init__(self, data = -1, next = None):
        self.data = data
        self.next = next
class List(object):
    def __init__(self, head=Node(-1)):
        self.head = head
        self.length = 0
    def __del__(self):
        del self.head
        self.length = 0
    @classmethod
    # 看了 装饰器才懂， 这会记忆化！！！
    def create(cls):
        obj = cls()
        return obj
    @staticmethod
    def printf(head) -> bool:
        if head == None:
            return False
        tmp = head
        while tmp.next != None:
            tmp = tmp.next
            print(tmp.data, end='')
        return True
    def insert(self, index, val) -> bool:  # 位置 & 值
        if self.head == None or index < 0 or index > self.size():
            return False
        tmp = self.head
        while index > 0:
            tmp = tmp.next
            index -= 1
        node = Node(val, tmp.next)
        tmp.next = node
        self.length += 1
        return True
    def delete(self, index) -> bool:  # 位置
        if self.head == None or index < 0 or index >= self.size():
            return False
        tmp = self.head
        while index > 0:
            tmp = tmp.next
            index -= 1
        tmp.next = tmp.next.next
        self.length -= 1
        return True
    def modify(self, index, val) -> bool:  # 位置 & 值
        if self.head == None or index < 0 or index >= self.size():
            return False
        tmp = self.head
        while index >= 0:
            tmp = tmp.next
            index -= 1
        tmp.data = val
        return True
    def find(self, val) -> int:  # return 位置
        tmp = self.head
        now = 0
        while tmp.next != None:
            tmp = tmp.next
            if tmp.data == val:
                return now
            now += 1
        return -1
    def size(self) -> int:
        return self.length
    def empty(self) -> bool:
        return self.head.next == None
if __name__ == '__main__':
    lis = List.create()
    lis.insert(0, 1)
    lis.insert(0, 2)
    lis.insert(1, 3)
    lis.insert(0, 4)
    lis.delete(3)
    List.printf(lis.head)
    lis.find(2)

class Node(object):
    def __init__(self, val):
        self.val = val
        self.pre = None
        self.next = None
class List(object):
    def __init__(self, head = Node(-1), tail = Node(-1)):
        self.head = head
        self.tail = tail
        head.next = tail
        tail.pre = head
        self.length = 0
    def __del__(self):
        del self.head
        del self.tail
        self.length = 0
    def insert(self, index, val):
        if index < 0 or index > self.size() or self.head == None:
            return False
        tmp = Node(val)
        cur = self.head
        while index > 0:
            cur = cur.next
            index -= 1
        tmp.next = cur.next
        cur.next = tmp
        tmp.next.pre = tmp
        tmp.pre = cur
        self.length += 1
        return True
    def delete(self, index):
        if index < 0 or index >= self.size() or self.head == None:
            return False
        cur = self.head
        while index > 0:
            cur = cur.next
            index -= 1
        cur.next = cur.next.next
        cur.next.pre = cur
        self.length -= 1
        return True
    def modify(self, index, val):
        if index < 0 or index >= self.size() or self.head == None:
            return False
        cur = self.head
        while index >= 0:
            cur = cur.next
            index -= 1
        cur.val = val
        return True
    def find(self, val):
        if self.head == None:
            return -1
        cur = self.head
        cnt = 0
        while cur.next != self.tail:
            cur = cur.next
            if cur.val == val:
                return cnt
            cnt += 1
        return -1
    def printf(self):
        cur = self.head
        while cur.next != self.tail:
            cur = cur.next
            print(cur.val, end='')
    def size(self):
        return self.length
    def empty(self):
        return size() == 0
    if __name__ == '__main__':
    lis = List()
    lis.insert(0, 1)
    lis.insert(0, 2)
    lis.insert(2, 3)
    lis.insert(1, 4)
    # 2413
    lis.printf()
    lis.delete(2)
    lis.delete(2)
    print()
    lis.printf()
    lis.modify(1, 0)
    print()
    lis.printf()
    lis.find(4)