Lintcode 384. Longest Substring Without Repeating Characters

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

Example

Example 1:

Input: "abcabcbb"
Output: 3
Explanation: The longest substring is "abc".

Example 2:

Input: "bbbbb"
Output: 1
Explanation: The longest substring is "b".

Challenge

time complexity O(n)

Code (Java):

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public class Solution {     /**      * @param s: a string      * @return: an integer      */     public int lengthOfLongestSubstring(String s) {         if (s == null || s.length() == 0) {             return 0;         }                   int[] count = new int[256];         int left = 0;         int maxLen = 0;                   for (int right = 0; right < s.length(); right++) {             char c = s.charAt(right);             count[c]++;                           // shrink left pointer             //             while (count[c] > 1) {                 count[s.charAt(left)]--;                 left++;             }                           maxLen = Math.max(maxLen, right - left + 1);         }                   return maxLen;               } }