FirstUniqueCharacterinaStringHashMap.java

/*Given a string s, find the first non-repeating character in it and return its index. If it does not exist, return -1.
Example 1:
Input: s = "leetcode"
Output: 0
Explanation:
The character 'l' at index 0 is the first character that does not occur at any other index.
Example 2:
Input: s = "loveleetcode"
Output: 2
Example 3:
Input: s = "aabb"
Output: -1
Constraints:
1 <= s.length <= 105
s consists of only lowercase English letters.*/
import java.util.*;
class FirstUniqueCharacterinaStringHashMap{
	public static void main(String[] args){
		Scanner sc=new Scanner(System.in);
		String s=sc.next();
		System.out.print(firstUniqChar(s));
	}
	public static int firstUniqChar(String s){
        Map<Character,Integer> map=new HashMap<>();
        int count=s.charAt(0);
        for(int i=0;i<s.length();i++){
            if(map.containsKey(s.charAt(i))){
                map.put(s.charAt(i),count++);
            }else{
                 map.put(s.charAt(i),1);
            }
        }
        for(int i=0;i<s.length();i++){
            if(map.get(s.charAt(i))==1) return i;
        }
        return -1;
	}
}