3.Longest Substring Without Repeating Characters

Longest Substring Without Repeating Characters

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

Examples:

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.

Solution

public class Solution {

    public int lengthOfLongestSubstring(String s){

        if(s == null) return 0;
        int sizeS = s.length();

        if(sizeS == 0) return 0; 

        int maxLength = 1;
        int start = 0;
        for(int i = 1; i < sizeS; i ++){

            char examineChar = s.charAt(i);

            int j = start;
            for(; j <= i - 1; j ++){
                if(examineChar == s.charAt(j)){
                    start = j + 1;
                    break;
                }
            }

            if (j == i)
                maxLength = (maxLength >(i - start + 1)) ? maxLength: i - start + 1;



        }

        return maxLength;
    }

    public static void main(String[] args) {
        Solution s = new Solution();

        System.out.println(s.lengthOfLongestSubstring("abcabc"));
    }
}