LeetCode 387. First Unique Character in a String

Description

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.

Code

class Solution {public:    int firstUniqChar(string s) {        if (s.size() == 1) return 0;        if (s == "") return -1;        int index[26]={0};        for (int i=0;i<s.size();i++)            index[s[i]-97] = index[s[i]-97]==0?i+1:s.size()+1;        int min=s.size()+1;        for (int i:index)            if (i != 0 && i < min)                min = i;        if (min != s.size() + 1) return min-1;        return -1;    }};

Appendix

• Link: https://leetcode.com/problems/first-unique-character-in-a-string/
• Run Time: 59ms