[Leetcode]3. Longest Substring Without Repeating Characters

题目描述

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.

• Example 4:

Input: s = ""
Output: 0

给定一个字符串，求最长不重复子串，本题主要考查滑动窗口和哈希表。

代码实现

import java.util.HashMap;
import java.util.Map;

class Solution {

  public int lengthOfLongestSubstring(String s) {
    int left = 0;
    int right = 0;
    //滑动窗口区间[left,right]
    int maxLen = 0;
    Map<Character, Integer> map = new HashMap<>();
    while (right < s.length()) {
      char c = s.charAt(right);
      if (map.containsKey(c)) {
        left = Math.max(left, map.get(c) + 1);
      }
      map.put(c, right);
      maxLen = Math.max(maxLen, right - left + 1);
      right++;
    }
    return maxLen;
  }

  public static void main(String[] args) {
    System.out.println(new Solution().lengthOfLongestSubstring("abcabcdbb"));
    System.out.println(new Solution().lengthOfLongestSubstring("bbbbb"));
    System.out.println(new Solution().lengthOfLongestSubstring("b"));
  }
}

[Leetcode]3. Longest Substring Without Repeating Characters

原文：https://www.cnblogs.com/strongmore/p/14287041.html