Find uncommon characters of the two strings | Set 2

• Difficulty Level : Medium
• Last Updated : 25 Nov, 2021

Given two strings, str1 and str2, the task is to find and print the uncommon characters of the two given strings in sorted order without using extra space. Here, an uncommon character means that either the character is present in one string or it is present in the other string but not in both. The strings contain only lowercase characters and can contain duplicates.

Examples:

Input: str1 = “characters”, str2 = “alphabets”
Output: b c l p r

Input: str1 = “geeksforgeeks”, str2 = “geeksquiz”
Output: f i o q r u z

Approach: An approach that uses hashing has been discussed here. This problem can also be solved using bit operations.
The approach uses 2 variables that store the bit-wise OR of the left shift of 1 with each character’s ASCII code – 97 i.e. 0 for ‘a’, 1 for ‘b’, and so on. For both the strings, we get an integer after performing these bit-wise operations. Now the XOR of these two integers will give the binary bit as 1 at only those positions that denote uncommon characters. Print the character values for those positions.

Below is the implementation of the above approach:

C++

 // C++ implementation of the approach#include using namespace std; // Function to print the uncommon// characters in the given string// in sorted ordervoid printUncommon(string str1, string str2){    int a1 = 0, a2 = 0;    for (int i = 0; i < str1.length(); i++) {         // Converting character to ASCII code        int ch = int(str1[i]) - 'a';         // Bit operation        a1 = a1 | (1 << ch);    }    for (int i = 0; i < str2.length(); i++) {         // Converting character to ASCII code        int ch = int(str2[i]) - 'a';         // Bit operation        a2 = a2 | (1 << ch);    }     // XOR operation leaves only uncommon    // characters in the ans variable    int ans = a1 ^ a2;     int i = 0;    while (i < 26) {        if (ans % 2 == 1) {            cout << char('a' + i);        }        ans = ans / 2;        i++;    }} // Driver codeint main(){    string str1 = "geeksforgeeks";    string str2 = "geeksquiz";     printUncommon(str1, str2);     return 0;}

Java

 // Java implementation of the approachclass GFG{     // Function to print the uncommon    // characters in the given string    // in sorted order    static void printUncommon(String str1, String str2)    {        int a1 = 0, a2 = 0;        for (int i = 0; i < str1.length(); i++)        {             // Converting character to ASCII code            int ch = (str1.charAt(i)) - 'a';             // Bit operation            a1 = a1 | (1 << ch);        }        for (int i = 0; i < str2.length(); i++)        {             // Converting character to ASCII code            int ch = (str2.charAt(i)) - 'a';             // Bit operation            a2 = a2 | (1 << ch);        }         // XOR operation leaves only uncommon        // characters in the ans variable        int ans = a1 ^ a2;         int i = 0;        while (i < 26)        {            if (ans % 2 == 1)            {                System.out.print((char) ('a' + i));            }            ans = ans / 2;            i++;        }    }     // Driver code    public static void main(String[] args)    {        String str1 = "geeksforgeeks";        String str2 = "geeksquiz";         printUncommon(str1, str2);    }} // This code contributed by Rajput-Ji

C#

 // C# implementation of the approachusing System; class GFG{     // Function to print the uncommon// characters in the given string// in sorted orderstatic void printUncommon(string str1, string str2){    int a1 = 0, a2 = 0;    for (int i = 0; i < str1.Length; i++)    {         // Converting character to ASCII code        int ch = (str1[i] - 'a');         // Bit operation        a1 = a1 | (1 << ch);    }    for (int i = 0; i < str2.Length; i++)    {         // Converting character to ASCII code        int ch = (str2[i] - 'a');         // Bit operation        a2 = a2 | (1 << ch);    }     // XOR operation leaves only uncommon    // characters in the ans variable    int ans = a1 ^ a2;     int j = 0;    while (j < 26)    {        if (ans % 2 == 1)        {            Console.Write((char)('a' + j));        }        ans = ans / 2;        j++;    }} // Driver codepublic static void Main(){    string str1 = "geeksforgeeks";    string str2 = "geeksquiz";     printUncommon(str1, str2); }} // This code is contributed by SoM15242

Python3

 # Python3 implementation of the approach # Function to print the uncommon# characters in the given string# in sorted orderdef printUncommon(str1, str2) :     a1 = 0; a2 = 0;         for i in range(len(str1)) :         # Converting character to ASCII code        ch = ord(str1[i]) - ord('a');         # Bit operation        a1 = a1 | (1 << ch);         for i in range(len(str2)) :         # Converting character to ASCII code        ch = ord(str2[i]) - ord('a');         # Bit operation        a2 = a2 | (1 << ch);     # XOR operation leaves only uncommon    # characters in the ans variable    ans = a1 ^ a2;     i = 0;    while (i < 26) :        if (ans % 2 == 1) :            print(chr(ord('a') + i),end="");                 ans = ans // 2;        i += 1; # Driver codeif __name__ == "__main__" :     str1 = "geeksforgeeks";    str2 = "geeksquiz";     printUncommon(str1, str2);         # This code is contributed by AnkitRai01

Javascript


Output:
fioqruz

Time Complexity: O(|str1| + |str2| + 26)Auxiliary Space: O(1)

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