Longest Substring Without Repeating Characters

最新推荐文章于 2025-05-18 01:04:12 发布

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最新推荐文章于 2025-05-18 01:04:12 发布

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原文链接：http://www.cnblogs.com/joannacode/p/5816535.html

本文介绍了一种使用滑动窗口和哈希映射的方法来寻找给定字符串中最长的无重复字符子串长度的算法。通过实例展示了如何实现该算法，并提供了完整的Java代码示例。

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.

HashMap

public class Solution {
    public int lengthOfLongestSubstring(String s) {
      int max = 0;
      int start = 0;
      int end = 0;
      if(s.isEmpty()){
          return 0;
      }
      max = 1;
      HashMap<Character, Integer> map = new HashMap<Character, Integer>();
      char stringArray[] = s.toCharArray();
      while(end < s.length()){
          if(map.containsKey(stringArray[end])){
              if((end - start) > max)
                max = end - start ;
              if(map.get(stringArray[end]) >= start)
                start = map.get(stringArray[end]) + 1 ;
          }
          map.put(stringArray[end], end);
          end++;
      }
      return Math.max(max, end - start);
    }
}

转载于:https://www.cnblogs.com/joannacode/p/5816535.html