387. 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.难度: easy题目：给定字符串，找出第一个不重复的字符，并返回其下标。如果不存在则返回－1.思路：数组分别记录下标与出现次数。Runtime: 10 ms, faster than 93.94% of Java online submissions for First Unique Character in a String.Memory Usage: 40 MB, less than 14.74% of Java online submissions for First Unique Character in a String.class Solution { public int firstUniqChar(String s) { int[] count = new int[26]; int[] index = new int[26]; int result = s.length(); for (int i = 0; i < result; i++) { char c = s.charAt(i); count[c - ‘a’]++; index[c - ‘a’] = i + 1; } for (int i = 0; i < 26; i++) { if (1 == count[i]) { result = Math.min(result, index[i] - 1); } } return result >= s.length() ? -1 : result; }}