Lecture 57:-  Sample Problem - Find one extra character in Java

To find one extra character in Java between two strings, you can compare the character frequencies in both strings. One of the strings will have an extra character with a count greater than the corresponding count in the other string.

Here's a Java method to find the extra character between two strings:

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public class ExtraCharacterFinder {    public static char findExtraCharacter(String str1, String str2) {        int[] freqCount = new int[26]; // Assuming input only contains lowercase English letters        // Update frequency count for characters in the first string        for (char ch : str1.toCharArray()) {            freqCount[ch - 'a']++;        }        // Update frequency count for characters in the second string        for (char ch : str2.toCharArray()) {            freqCount[ch - 'a']--;        }        // Find the extra character in the second string        char extraChar = 0;        for (int i = 0; i < 26; i++) {            if (freqCount[i] < 0) {                extraChar = (char) ('a' + i);                break;            }        }        return extraChar;    }    public static void main(String[] args) {        String str1 = "abcdef";        String str2 = "abcdegf";        char extraChar = findExtraCharacter(str1, str2);        if (extraChar != 0) {            System.out.println("Extra character: " + extraChar); // Output: Extra character: g        } else {            System.out.println("No extra character found.");        }    } }

In this example, we have a method findExtraCharacter that takes two strings str1 and str2 as input and returns the extra character in str2. We initialize an array freqCount of size 26 to store the frequency count of characters (assuming input only contains lowercase English letters).

We first update the frequency count for characters in str1 and then subtract the frequency count for characters in str2. The difference in frequency count will give us the extra character. If the difference is less than 0 for any character, it means that character is the extra character in str2.

In the main method, we test the findExtraCharacter method with two sample strings. If an extra character is found, it will be printed; otherwise, it will print “No extra character found.”