LeetCode(003)- Longest Substring Without Repeating Characters

题目: Longest Substring Without Repeating Characters

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.

翻译：

给定一个字符串，在不重复字符的情况下找出最长子字符串的长度。
示例1:
输入:“abcabcbb”
输出:3
说明:答案是“abc”，长度为3。
示例2:
输入:“bbbbb”
输出:1
说明:答案是“b”，长度为1。
示例3:
输入:“pwwkew”
输出:3
说明:答案为“wke”，长度为3。
注意，答案必须是子字符串，“pwke”是子序列，而不是子字符串。进入翻译页面

思路：请查看此篇文章思路：无重复元素的最长子串（移动滑块解法）

class Solution {
    public int lengthOfLongestSubstring(String s) {
        if(s==null || s.length()==0){
            return 0;
        }else if(s.length()==1){
            return 1;
        }
        int start=0; //子串开始坐标
        int end=0;//结束坐标下一位；
        int maxLen=0; //当前最长子串长度；
        while(end<s.length()){
            for(int i=start ; i<end ; i++){
                if(s.charAt(i)==s.charAt(end)){ //有重复元素，
                    start=i+1;
                    if(s.length()-start<= maxLen){ 
                    //未检测子串长度小于已获得子串长度，没有必要在去匹配
                       return maxLen;
                   }  
                }
                break;
            }
            maxLen=maxLen > end-start+1 ? maxLen : end-start+1 ;
            end++;
        }
        return maxLen  ;
        
    }
}