快慢指针算法

 

 

<script>
    var str = 'aaaaaaaaaaaabababbbbbbbbbbbbcccccccccccccccccdddd'
    var fir = 0,
    maxLen = 0
    for(var i = 1; i < str.length; i++) {
      // console.log(str[i])
      if(str[fir] != str[i]) {
        console.log(i-fir)
        fir = i
      }
      if((i+1) == str.length) {
        console.log((i+1)-fir)
      }
    }
  </script>