代码:
int lengthOfLongestSubstring(string s) {
int len=s.length();
int maxLen=0;
int start=-1;
map<char,int> mp; //用 map做映射
for(int i=0;i<len;i++){
if(mp.count(s[i])){
start=max(start,mp[s[i]]); //更新坐标,删除左边界无用点
}
mp[s[i]]=i;
maxLen=max(maxLen,i-start);
}
return maxLen;
}