LEETCODE--First Unique Character in a String

Given a string, find the first non-repeating character in it and return it’s index. If it doesn’t exist, return -1. Examples: s = “leetcode” return 0.

s = “loveleetcode”, return 2. Note: You may assume the string contain only lowercase letters.

class Solution { public: int firstUniqChar(string s) { int alph[26] = {0}; for(int i = 0; i < s.length(); i++){ if(alph[s[i] - 'a'] == 0){ alph[s[i] - 'a'] = 1; int j = i + 1; for(; j < s.length(); j++){ if(s[i] == s[j]) break; } if(j == s.length()) return i; } } return -1; } };