You need to write a function, which will accept a String and return first non-repeated character, for example in the world "hello", except 'l' all are non-repeated, but 'h' is the first non-repeated character. Similarly, in word "swiss" 'w' is the first non-repeated character. One way to solve this problem is creating a table to store count of each character, and then picking the first entry which is not repeated. The key thing to remember is order, your code must return first non-repeated letter.

1 public class solution { 2     public char firstNonRepeating(String s) { 3         char result = '#'; 4         if (s == null || s.length == 0) { 5             return result; 6         } 7         Map
     
       map = HashMap<>(); 8         for (int i = 0; i < s.length(); i++) { 9             if (map.containsKey(s.charAt(i))) {10                 map.put(s.charAt(i), map.get(s.charAt(i)) + 1);11             } else {12                 map.put(s.charAt(i), 1);13             }14         }15 16         for (int i = 0; i < s.length; i++) {17             if (map.get(s.charAt(i) == 1)) {18                 result = s.charAt(i);    19                 return result;20             }21         }22         return result; 23     }24 }