T1 LC983 最低票价

动态规划，倒序生成，需要使用@lru_cache(None)

  1. class Solution:
  2.     def mincostTickets(self, days: List[int], costs: List[int]) -> int:
  3.         duration =[1,7,30]
  5.         @lru_cache(None)
  6.         def dp(i):
  7.             if i>365:return 0
  8.             elif i in days:
  9.                 return min(dp(i+d)+c for c,d in zip(costs,duration))
  10.             else:return dp(i+1)
  11.         return dp(1)

T2 LC1290 二进制链表转整数

  1. class Solution {
  2. public:
  3.     int getDecimalValue(ListNode* head) {
  4.         long long result=0;
  5.         while (head) {
  6.             result = result * 2 + head->val;
  7.             head = head->next;
  8.         }
  9.         return result;
  10.     }
  11. };

T3 LC468 验证IP地址

使用基础函数库加正则表达式

  1. import re
  2. class Solution:
  3.     chunk_IPv4 = r'([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])'
  4.     patten_IPv4 = re.compile(r'^(' + chunk_IPv4 + r'\.){3}' + chunk_IPv4 + r'$')
  6.     chunk_IPv6 = r'([0-9a-fA-F]{1,4})'
  7.     patten_IPv6 = re.compile(r'^(' + chunk_IPv6 + r'\:){7}' + chunk_IPv6 + r'$')
  9.     def validIPAddress(self, IP: str) -> str:        
  10.         if '.' in IP:
  11.             return "IPv4" if self.patten_IPv4.match(IP) else "Neither" 
  12.         if ':' in IP:
  13.             return "IPv6" if self.patten_IPv6.match(IP) else "Neither" 
  14.         return "Neither"

今日学习总结

完成计网作业

完成托福练习