Java: Find the index of first non-repeating character in a given string
Java Basic: Exercise-187 with Solution
Write a Java program to find the index of the first non-repeating character in a given string.
Pictorial Presentation:

Sample Solution:
Java Code:
import java.util.*;
public class Solution {
public static void main(String[] args) {
String str1 = "google";
System.out.println("Index of first non-repeating character in '" + str1 + "' is: " + first_unique_character(str1));
}
public static int first_unique_character(String str1) {
HashMap < Character, Integer > map = new HashMap < > ();
for (int i = 0; i < str1.length(); ++i) {
char chr = str1.charAt(i);
map.put(chr, map.containsKey(chr) ? map.get(chr) + 1 : 1);
}
for (int i = 0; i < str1.length(); ++i) {
if (map.get(str1.charAt(i)) < 2) {
return i;
}
}
return -1;
}
}
Sample Output:
Index of first non-repeating character in 'google' is: 4
Flowchart:

Java Code Editor:
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