[LeetCode]無重複字符的最長子串

題目如題：

輸入樣例：

abba

輸出:

2

C++ 代碼

class Solution {
public:
    int lengthOfLongestSubstring(string s) {
        map<char, int> data;
        int max = 0;
        int i, j;
        for(i = 0, j = 0; i < s.length(); i++){
            if(data.count(s[i]) && data[s[i]] >= j){
                max = ((i - 1) - j + 1) > max? ((i - 1) - j + 1) : max;
                j = data[s[i]]+1;
                data[s[i]] = i;
            }else{
                data[s[i]] = i;
            }
        }
        max = max > ((i-1-j+1)) ? max : (i-1-j+1);
        return max;
    }
};