//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 FirstUniqueCharacterInAString {

public int firstUniqChar(String s) {

HashMap<Character, Integer> characters = new HashMap<Character, Integer>();

for(int i = 0; i < s.length(); i++) {

char current = s.charAt(i);

if(characters.containsKey(current)) {

characters.put(current, -1);

} else {

characters.put(current, i);

}

}

int min = Integer.MAX_VALUE;

for(char c: characters.keySet()) {

if(characters.get(c) > -1 && characters.get(c) < min) {

min = characters.get(c);

}

}

return min == Integer.MAX_VALUE ? -1 : min;

}

}