LeetCode 3. Longest Substring Without Repeating Characters （Medium）
作者：互联网
题目
Given a string s, find the length of the longest substring without repeating characters.
Example 1:
Input: s = "abcabcbb"
Output: 3
Explanation: The answer is "abc", with the length of 3.
Example 2:
Input: s = "bbbbb"
Output: 1
Explanation: The answer is "b", with the length of 1.
Example 3:
Input: s = "pwwkew"
Output: 3
Explanation: The answer is "wke", with the length of 3.
Notice that the answer must be a substring, "pwke" is a subsequence and not a substring.
Constraints:
0 <= s.length <= 5 * 104
s consists of English letters, digits, symbols and spaces.
思路
解法（Java）
class Solution {
public int lengthOfLongestSubstring(String s) {
if(s == null || s.length() == 0) return 0;
Map<Character, Integer> map = new HashMap<>();
int left = 0, right = 0, len = 1;
for(int i = 0; i < s.length(); i++){
char ch = s.charAt(i);
if(map.containsKey(ch)){
// 对left的更新
left = Math.max(left, map.get(ch)+1);
}
map.put(ch, i);
len = Math.max(len, right-left+1);
right++;
}
return len;
}
}
标签：map,Medium,len,Substring,length,ch,answer,Without,left 来源： https://www.cnblogs.com/amiya2021/p/15747300.html