Longest Substring Without Repeating Characters思路

题目

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.

来源：力扣（LeetCode）
链接：https://leetcode-cn.com/problems/longest-substring-without-repeating-characters
著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。

思路

1. 需要一个可以记录字符串最大值的变量 maxLen
2. 实现这个规则结构：
   • 不停的往这个结构中输入字符串s中的按序字符
   • 若未遇上相同的字符，结构长度累计 maxLen + 1
   • 若遇上相同字符，则放弃接近头部相同的字符之前的部分，计入此字符
3. 注意边界及何时更新 maxLen

实现

/**
 * @param {string} s
 * @return {number}
 */
var lengthOfLongestSubstring = function(s) {
    let maxLen = 0;
    const list = s.split('');
    const map = {};
    let templist = [];
    list.forEach(c => {
        if (map[c]) {
            let i = templist.length;
            while(i) {
              if (templist[i - 1] === c) {
                const l = templist.splice(0, i);
                l.forEach(c => {
                  map[c] = 0;
                })
              }
              i--;
            }
            templist.push(c);
            map[c] = 1;
        } else {
            templist.push(c);
            map[c] = 1;
            maxLen = templist.length > maxLen ? templist.length : maxLen;
        }
    })
    return maxLen;
};