Leetcode3: Longest Substring Without Repeating Characters
具体题目如下:
Given a string, find the length of the longest substring without repeating characters.
Example 1:
Input: “abcabcbb”
Output: 3
Explanation: The answer is “abc”, with the length of 3.
Example 2:
Input: “bbbbb”
Output: 1
Explanation: The answer is “b”, with the length of 1.
Example 3:
Input: “pwwkew”
Output: 3
Explanation: 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.
思路很简单,从左到右遍历,把不重复字符串放进列表中(result),如果有重复的,则先获取重复字符所在的位置index,从该位置的下一个值开始,到result的最后一个值,作为新的子串,并把当前字符存进新的result中,同时每一次遍历时记录最长的不重复子串,放在best中,遍历结束后,best的长度就是最长的不重复子串。具体看代码:
class Solution:
def lengthOfLongestSubstring(self, s):
"""
:type s: str
:rtype: int
"""
result = list()
best = list()
if len(s) == 1:
return 1
for num,i in enumerate(s):
if i in result:
index = result.index(i)
result = result[index+1:]
result.append(i)
if len(best) < len(result):
best = list(result)
return len(best)