lengthOfLongestSubstring.js

/*
 * @Author: Z1hgq
 * @Date: 2019-09-17 14:26:50
 * @LastEditTime: 2019-09-17 18:07:46
 */

/**
 * @param {string} s
 * @return {number}
 */

const lengthOfLongestSubstring = function (s) {
  let res = 0;
  let i = 0;
  const temp = [];
  while (i < s.length) {
    if (temp.indexOf(s[i]) === -1) { // 如果不存在的话向数组里继续添加
      temp.push(s[i]);
    } else {
      temp.shift(); // 如果存在的话表明当前这个子串不符合无重复字符的要求，删除队头的元素，跳出这次循环
      continue;
    }
    res = Math.max(res, temp.length);
    i++;
  }
  return res;
};

// 超时
const lengthOfLongestSubstringII = function (s) {
  if (s === "") return 0;
  for (let i = s.length; i > 0; i--) {
    let j = 0;
    while (j + i <= s.length) {
      const str = s.slice(j, j + i);
      if (s.indexOf(str) != -1) {
        const strSet = new Set(str);
        if (Array.from(strSet).length === str.length) {
          return str.length;
        } else {
          j++;
        }
      } else {
        j++;
      }
    }
  } 
};
console.log(lengthOfLongestSubstring("dvuadbiabkhbcacbnaosbduioheqwoehoiqwjojojaddddddddddddddohwdoboubqibibiuabisbdoahdiqowhdpqwpojlcnklasnclknalkdf"));