Given a string, find the length of the longest substring without repeating characters.
Examples:
Given "abcabcbb", the answer is "abc", which the length is 3.
Given "bbbbb", the answer is "b", with the length of 1.
Given "pwwkew", the answer is "wke", with the length of 3. Note that the answer must be a substring, "pwke" is a subsequenceand not a substring.
/**
* @param {string} s
* @return {number}
*/
var lengthOfLongestSubstring = function(s) {
//这道题是为了找到最长的连续不重复的字符串长度
//可以先过滤掉所有的不重复字符串
var i,j=0;
var lastStr="";
var maxLength=0;
for(i=0;i<s.length;){
if(lastStr.indexOf(s[i])==-1){
lastStr=lastStr.concat(s[i++])
maxLength=Math.max(maxLength,i-j);
}else{
lastStr=lastStr.slice(1);
j++;
}
}
return maxLength;
};