zoukankan      html  css  js  c++  java
  • 3. 无重复字符的最长子串

    3. 无重复字符的最长子串

    问题描述

    Given a string, find the length of the longest substring without repeating characters.

    Example

    Given "abcabcbb", the answer is "abc", which the length is 3.
    Given "bbbbb", the answer is "b", with the length of 1.
    Given "pwwkew", the answer is "wke", with the length of 3. Note that the answer must be a substring, "pwke" is a subsequence and not a substring.

    思路

    问题即是求字符串中的最长子序列。

    1. low方法:循环解决

      双重循环,判断是否字符在子序列中。

    2. NB方法:放入字典

      字典中存放字符及其出现的位置索引,不断更新。

    class Solution:
        def lengthOfLongestSubstring0(self, s):
            """
            :type s: str
            :rtype: int
            """
            max_length = 0
            if (len(s) == 1 or len(s) == 0):
                max_length = len(s)
            for i in range(0, len(s)-1):
                for j in range(i+1, len(s)):
                    if s[j] in s[i:j]:
                        if j - i > max_length:
                            max_length = j - i
                        break
                    elif j == len(s) - 1:
                        if max_length < j - i + 1:
                            max_length = j -i + 1
            return max_length
    
        def lengthOfLongestSubstring(self, s):
            indexDict = {}
            maxLength = currMax = 0
    
            for i in range(len(s)):
                if s[i] in indexDict and i - indexDict[s[i]] - 1 <= currMax:
                    if maxLength < currMax:
                        maxLength = currMax
                    currMax = i - indexDict[s[i]] - 1
                currMax = currMax + 1
                indexDict[s[i]] = i
    
            return maxLength if currMax < maxLength else currMax
    
    
    if __name__ == '__main__':
        solution = Solution()
        max_length = solution.lengthOfLongestSubstring('abcabcbb')
        print(max_length)
    

    GitHub地址:https://github.com/protea-ban/LeetCode

  • 相关阅读:
    开发avr单片机网络资源
    c语言中各种数据类型的长度
    REPEAT_BYTE(x)宏
    如何快速掌握man手册的使用
    如何获取内核代码的变更信息说明
    min宏的学习
    Spring对jdbc支持
    切入点表达式
    XML方式实现AOP编程
    注解方式实现AOP编程
  • 原文地址:https://www.cnblogs.com/banshaohuan/p/9597616.html
Copyright © 2011-2022 走看看