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 length = s.length(); String str; for(int i=0;i<length;i++){ if(i==length-1){ str = s.substring(0, i); } else{ str = s.substring(0,i)+s.substring(i+1); } if(!str.contains(s.charAt(i)+"")) return i; } return -1; } } Try it on Leetcode Here, we are going to use substring method. 1) If character is at end, then take substring from 0 till before last character of string. 2) Else make a temporary string, by removing exactly that particular character using index. [e.g..