第 3 期(2019-05-10)：无重复字符的最长子串 #4

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1. binperson

   changed the title [-]第 2 期(2019-05-10)：无重复字符的最长子串[/-] [+]第 3 期(2019-05-10)：无重复字符的最长子串[/+] on May 10, 2019
2. cnyballk commented on May 10, 2019

   

   cnyballk

   on May 10, 2019

   More actions

   const get666Length = s => {
     if (s.length < 2) return s.length;
     let index,
       i = 1,
       discardLength = 0,
       max = 0;
     for (; i < s.length; i++) {
       index = s.lastIndexOf(s[i], i - 1);
       if (index !== -1) {
         max = Math.max(max, i - discardLength);
         discardLength = Math.max(discardLength, index + 1);
       }
     }
     return Math.max(max, i - discardLength);
   };

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3. wingmeng commented on May 11, 2019

   

   wingmeng

   on May 11, 2019

   Collaborator

   More actions

   这题还是有点难度的，一开始是打算用“双指针”来解的，后来感觉用正则表达式更优雅。

   const noRepeatSubstrLen = str => {
     let len = str ? str.length : 0;
   
     // 空字符和1个字符的情况
     if (len < 2) {
       return len;
     }
   
     let arr = [
       ...new Set(  // 去重
         str.split(/(.+?)(\1)/g)  // 贪婪模式匹配所有连续字符
       )
     ].map(s => s.length);  // 去重后统计每项的字符串长度
     
     return Math.max.apply(null, arr);
   }
   
   console.log(noRepeatSubstrLen(''));  // 0
   console.log(noRepeatSubstrLen('a'));  // 1
   console.log(noRepeatSubstrLen('ab'));  // 2
   console.log(noRepeatSubstrLen('aa'));  // 1
   console.log(noRepeatSubstrLen('abcabcbb'));  // 3
   console.log(noRepeatSubstrLen('bbbbb'));  // 1
   console.log(noRepeatSubstrLen('pwwkew'));  // 3
   console.log(noRepeatSubstrLen('qqwewert'));  // 2

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4. liwenkang commented on May 11, 2019

   

   liwenkang

   on May 11, 2019

   More actions

   我的怕是会超时⊙﹏⊙

   // 求无重复字符的最长子串
   const getMaxCount = (string) => {
       // 计算最长不重复连续字符的个数
       const getCount = (string, lastStr = '') => {
           lastStr = lastStr ? lastStr : string[0];
           for (let i = 1; i < string.length; i++) {
               if (lastStr.includes(string[i])) {
                   // 有重复的,直接输出
                   return lastStr.length;
               } else {
                   // 没有重复的,继续循环
                   lastStr += string[i];
                   getCount(string, lastStr);
               }
           }
           return lastStr.length;
       };
   
       let max = 0;
       for (let i = 0; i < string.length; i++) {
           let count = getCount(string.slice(i));
           if (count > max) {
               max = count;
           }
       }
       return max;
   };