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387. first unique character in a string 解答

admin 11月 13, 2020 0

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.

解答

public class Solution {
    public int firstUniqChar(String s) {
        int freq [] = new int[26];
        for(int i = 0; i < s.length(); i ++)
            freq [s.charAt(i) - 'a'] ++;
        for(int i = 0; i < s.length(); i ++)
            if(freq [s.charAt(i) - 'a'] == 1)
                return i;
        return -1;
    }
}