/*     * 3. Longest Substring Without Repeating Characters      * 2016-4-10 by Mingyang     * 直接用array代替map，注意遇到重复的替换的是地图里面前一个加1     */      public int lengthOfLongestSubstring(String s) {            int len=s.length();            if(s==null||len==0)              return 0;            int start=0;            int[] count=new int[256];            Arrays.fill(count,-1);            int max=Integer.MIN_VALUE;            for(int i=0;i
     
      =start){                   start=count[s.charAt(i)]+1;                }                 max=Math.max(max,i-start+1);                 count[s.charAt(i)]=i;            }            return max;        }