C++：哈希+双指针
找到字符串的最长无重复字符子串
http://www.nowcoder.com/questionTerminal/b56799ebfd684fb394bd315e89324fb4
#include<unordered_map>
class Solution {
public:
int maxLength(vector<int>& arr) {
unordered_map<int , int> mymap;
int i = 0 , Max = INT_MIN;
while(i<arr.size())
{
mymap.clear();
mymap[arr[i]] = i;
int j = i+1;
while(j<arr.size())
{
if(mymap.count(arr[j])==0)//返回匹配特定键的元素数量
{
mymap[arr[j]] = j;
}
else
{
i = mymap.at(arr[j]);//访问指定键值的元素
break;
}
j++;
}
i++;
int temp = mymap.size();
Max = max(Max , temp);
}
return Max;
}
}; 