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.

Note: You may assume the string contain only lowercase letters.

这道题按照383. Ransom Note的思路，若s仅由小写字符组成，那么创建一个26的int数组，并将次数存入到result数组的相应位置（例如a的次数存入到result[0]中），然后遍历s，当s的某个元素次数为1时，则返回对应的i值，若均不存在1，则返回-1。

public class fuzhi {   public int firstUniqChar(String s){ int[] result = new int[26]; for(int i =0;i<s.length();i++){ result[s.charAt(i)-'a']++; } for(int i=0;i<s.length();i++){ if(result[s.charAt(i)-'a']==1){ return i; } }return -1;}   public static void main(String[] args){    String s="leetcode";    fuzhi r = new fuzhi();     System.out.println(r.firstUniqChar(s));    }}