fix:二进制的题

02-链表/problem_solving_09.py

+"""
+回文链表
+"""
+from typing import Optional
+
+
+class ListNode:
+    def __init__(self, val=0, next=None):
+        self.val = val
+        self.next = next
+
+
+class Solution:
+    def isPalindrome(self, head: Optional[ListNode]) -> bool:
+        """
+        回文链表
+        :param head:
+        :return:
+        """
+        contain = []
+        curr = head
+        while curr is not None:
+            contain.append(curr.val)
+            curr = curr.next
+        curr2 = head
+        while curr2 is not None:
+            if contain.pop() != curr2.val:
+                return False
+            curr2 = curr2.next
+        return True
+
+
+if __name__ == '__main__':
+    # 1, 2, 6, 3, 4, 5, 6
+    l1 = ListNode(1)
+    l1.next = ListNode(2)
+    l1.next.next = ListNode(3)
+    l1.next.next.next = ListNode(3)
+    l1.next.next.next.next = ListNode(2)
+    l1.next.next.next.next.next = ListNode(1)
+    # l1.next.next.next.next.next.next = ListNode(7)
+    # l2 = ListNode(5)
+    # l2.next = ListNode(6)
+    # l2.next.next = ListNode(1)
+    # l2.next.next.next = ListNode(8)
+    # l2.next.next.next.next = ListNode(4)
+    # l2.next.next.next.next.next = ListNode(5)
+    result = Solution().isPalindrome(l1)
+    print(result)

02-链表/problem_solving_10.py

+"""
+链表的中间结点
+"""
+from typing import Optional
+
+
+class ListNode:
+    def __init__(self, val=0, next=None):
+        self.val = val
+        self.next = next
+
+
+class Solution:
+    def middleNode(self, head: Optional[ListNode]) -> Optional[ListNode]:
+        """
+        链表的中间结点,如果有2个 返回第二个  快慢指针
+        :param head:
+        :return:
+        """
+        fast, slow = head, head
+        while fast and fast.next:
+            slow = slow.next
+            fast = fast.next.next
+        return slow
+
+
+if __name__ == '__main__':
+    # 1, 2, 6, 3, 4, 5, 6
+    l1 = ListNode(1)
+    l1.next = ListNode(2)
+    l1.next.next = ListNode(3)
+    l1.next.next.next = ListNode(3)
+    l1.next.next.next.next = ListNode(2)
+    l1.next.next.next.next.next = ListNode(1)
+    # l1.next.next.next.next.next.next = ListNode(7)
+    # l2 = ListNode(5)
+    # l2.next = ListNode(6)
+    # l2.next.next = ListNode(1)
+    # l2.next.next.next = ListNode(8)
+    # l2.next.next.next.next = ListNode(4)
+    # l2.next.next.next.next.next = ListNode(5)
+    result = Solution().middleNode(l1)
+    while result:
+        print(result.val, end=' -> ')
+        result = result.next

06-二进制/problem_solving_01.py

+"""
+二进制链表转整数
+"""
+from typing import Optional
+
+
+class ListNode:
+    def __init__(self, val=0, next=None):
+        self.val = val
+        self.next = next
+
+
+class Solution:
+    def getDecimalValue(self, head: ListNode) -> int:
+        """
+        二进制链表转整数:头节点是高位
+        :param head:
+        :return:
+        """
+        res = 0
+        while head:
+            # *2相当于左移一位
+            res = res * 2 + head.val
+            head = head.next
+        return res
+
+
+if __name__ == '__main__':
+    # 头节点是高位
+    # 1, 2, 6, 3, 4, 5, 6
+    l1 = ListNode(1)
+    l1.next = ListNode(0)
+    l1.next.next = ListNode(1)
+    # l1.next.next.next = ListNode(3)
+    # l1.next.next.next.next = ListNode(2)
+    # l1.next.next.next.next.next = ListNode(1)
+    # l1.next.next.next.next.next.next = ListNode(7)
+    # l2 = ListNode(5)
+    # l2.next = ListNode(6)
+    # l2.next.next = ListNode(1)
+    # l2.next.next.next = ListNode(8)
+    # l2.next.next.next.next = ListNode(4)
+    # l2.next.next.next.next.next = ListNode(5)
+    result = Solution().getDecimalValue(l1)
+    print(result)
+    # while result:
+    #     print(result.val, end=' -> ')
+    #     result = result.next

888-设计题/problem_solving_10.py

+"""
+设计哈希集合
+"""
+
+
+class MyHashSet:
+
+    def __init__(self):
+        self.buckets = 1000
+        self.itemsPerBucket = 1001
+        self.table = [[] for _ in range(self.buckets)]
+
+    def hash(self, key):
+        return key % self.buckets
+
+    def pos(self, key):
+        return key // self.buckets
+
+    def add(self, key):
+        hashkey = self.hash(key)
+        if not self.table[hashkey]:
+            self.table[hashkey] = [0] * self.itemsPerBucket
+        self.table[hashkey][self.pos(key)] = 1
+
+    def remove(self, key):
+        hashkey = self.hash(key)
+        if self.table[hashkey]:
+            self.table[hashkey][self.pos(key)] = 0
+
+    def contains(self, key):
+        hashkey = self.hash(key)
+        return (self.table[hashkey] != []) and (self.table[hashkey][self.pos(key)] == 1)
+
+
+if __name__ == '__main__':
+    # 1, 2, 6, 3, 4, 5, 6
+    hash_set = MyHashSet()
+    result1 = hash_set.add(1)
+    result2 = hash_set.add(2)
+    result3 = hash_set.contains(1)
+    print(result1)
+    print(result2)
+    print(result3)