[编程练习][Longest Substring Without Repeating Characters]<LeetCode-3>
来源:互联网 发布:知乎怎么提问 编辑:程序博客网 时间:2024/06/10 05:22
题目来自https://oj.leetcode.com/problems/longest-substring-without-repeating-characters/
Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without repeating letters for "abcabcbb" is "abc", which the length is 3. For "bbbbb" the longest substring is "b", with the length of 1.
我的解答:
class Solution: # @return an integer def lengthOfLongestSubstring(self, s): start, curlen, findlen = 0,0, 0 Seen = dict() lenstr = len(s) for i in range(lenstr): ch = s[i] if ch not in Seen or Seen[ch] < start: curlen += 1 else: if curlen > findlen: findlen = curlen start = Seen[ch] + 1 curlen = i - Seen[ch] Seen[ch] = i #if found at end if curlen > findlen: findlen = curlen return findlen
说明:
这一题的难度标注为“Medium", 算是中规中矩吧。
我的思路是构造字典,记录出现过的字符的位置。从头开始扫描,统计无重复字符串的长度。
当前字符ch没有重复出现,则更新当前子串的无重复长度。start 指的是新串起始位置。
if ch not in Seen or Seen[ch] < start: curlen += 1重复出现,则检查是否是当前最大解,是则更新。记录新串起始位置和新串长度(利用Seen[ch]
else: if curlen > findlen: findlen = curlen start = Seen[ch] + 1 curlen = i - Seen[ch] Seen[ch] = i
程序很简单,重点是利用Seen[ch]来生成每次重新开始新串的起始位置和既有长度。
Python 的字典又一次发挥了作用。
0 0
- [编程练习][Longest Substring Without Repeating Characters]<LeetCode-3>
- Leetcode练习 #3Longest Substring Without Repeating Characters
- leetcode编程题(3)Longest Substring Without Repeating Characters
- LeetCode 3 - Longest Substring Without Repeating Characters
- LeetCode 3: Longest Substring Without Repeating Characters
- leetcode-3:Longest Substring Without Repeating Characters
- LeetCode(3) Longest Substring Without Repeating Characters
- leetcode 3LONGEST SUBSTRING WITHOUT REPEATING CHARACTERS
- Leetcode【3】:Longest Substring Without Repeating Characters
- [leetcode 3] Longest Substring Without Repeating Characters
- [Leetcode] 3 - Longest Substring Without Repeating Characters
- LeetCode 3:《Longest Substring Without Repeating Characters》
- [leetcode 3] Longest Substring Without Repeating Characters
- [leetcode] 3 Longest Substring Without Repeating Characters
- [Leetcode]3Longest Substring Without Repeating Characters
- leetcode 3 Longest Substring Without Repeating Characters
- LeetCode #3 Longest Substring Without Repeating Characters
- leetcode-3 Longest Substring Without Repeating Characters
- Android ViewPager使用详解
- 我的研究之预处理
- scrollTo 以及 scrollBy方法使用说明
- winpcap学习(1)基本介绍
- rcl
- [编程练习][Longest Substring Without Repeating Characters]<LeetCode-3>
- 设计模式之工厂模式
- 近况工作总结
- Jedis connection refused
- hdu 4901 The Romantic Hero (dp)
- Postgresql function
- 使用Python脚本编写网络爬出程序,来获取Web数据的方法实现(1)——流程图
- 用Springmvc传文件
- 利用chrome自带工具分析http包