Compare two strings considering only alphanumeric characters
Given two strings that can contain lower and uppercase alphabets, numbers and special characters like dots, blank spaces, commas, etc. Compare both strings considering only alphanumeric characters([a-b], [A-B] and [0-9]) if they are equal or not. For example, strings “Ram, Shyam” and “Ram-Shyam” both are the same and also “/.’;[]” and “@# >” are same.
Examples:
Input: str1 = "Ram, Shyam", str2 = " Ram - Shyam." Output: Equal Explanation: if we ignore all characters except alphanumeric characters then strings will be, str1 = "RamShyam" and str2 = "RamShyam". Therefore both strings are equal. Input : str1 = "aaa123", str2 = "@aaa-12-3" Output : Equal Input : str1 = "abc123", str2 = "123abc" Output : Unequal Explanation: In this, str1 = "abc123" and str2 = "123abc". Therefore both strings are not equal.
Since we have to compare only alphanumeric characters therefore whenever any other character is found simply ignore it by increasing iterator pointer. For doing it simply take two integer variables i and j and initialize them by 0. Now run a loop to compare each and every character of both strings. Compare one by one if the character is alphanumeric otherwise increase the value of i or j by one.
Below is the implementation of the above approach:
C++
#include <iostream> using namespace std; // Function to check alphanumeric equality of both strings bool CompareAlphanumeric(string& str1, string& str2) { // variable declaration int i, j; i = 0; j = 0; // Length of first string int len1 = str1.size(); // Length of second string int len2 = str2.size(); // To check each and every characters of both string while (i <= len1 && j <= len2) { // If the current character of the first string is not an // alphanumeric character, increase the pointer i while (i < len1 && (!((str1[i] >= 'a' && str1[i] <= 'z' ) || (str1[i] >= 'A' && str1[i] <= 'Z' ) || (str1[i] >= '0' && str1[i] <= '9' )))) { i++; } // If the current character of the second string is not an // alphanumeric character, increase the pointer j while (j < len2 && (!((str2[j] >= 'a' && str2[j] <= 'z' ) || (str2[j] >= 'A' && str2[j] <= 'Z' ) || (str2[j] >= '0' && str2[j] <= '9' )))) { j++; } // if all alphanumeric characters of both strings are same // then return true if (i == len1 && j == len2) return true ; // if any alphanumeric characters of both strings are not same // then return false else if (str1[i] != str2[j]) return false ; // If current character matched, // increase both pointers to check the next character else { i++; j++; } } // If not same, then return false return false ; } // Function to print Equal or Unequal if strings are same or not void CompareAlphanumericUtil(string str1, string str2) { bool res; // check alphanumeric equality of both strings res = CompareAlphanumeric(str1, str2); // if both are alphanumeric equal, print Equal if (res == true ) cout << "Equal" << endl; // otherwise print Unequal else cout << "Unequal" << endl; } // Driver code int main() { string str1, str2; str1 = "Ram, Shyam" ; str2 = " Ram - Shyam." ; CompareAlphanumericUtil(str1, str2); str1 = "abc123" ; str2 = "123abc" ; CompareAlphanumericUtil(str1, str2); return 0; } |
Java
// Java implementation of the approach import java.util.*; class GFG { // Function to check alphanumeric // equality of both strings static boolean CompareAlphanumeric( char [] str1, char [] str2) { // variable declaration int i, j; i = 0 ; j = 0 ; // Length of first string int len1 = str1.length; // Length of second string int len2 = str2.length; // To check each and every characters // of both string while (i <= len1 && j <= len2) { // If the current character of the first string is not an // alphanumeric character, increase the pointer i while (i < len1 && (!((str1[i] >= 'a' && str1[i] <= 'z' ) || (str1[i] >= 'A' && str1[i] <= 'Z' ) || (str1[i] >= '0' && str1[i] <= '9' )))) { i++; } // If the current character of the second string is not an // alphanumeric character, increase the pointer j while (j < len2 && (!((str2[j] >= 'a' && str2[j] <= 'z' ) || (str2[j] >= 'A' && str2[j] <= 'Z' ) || (str2[j] >= '0' && str2[j] <= '9' )))) { j++; } // if all alphanumeric characters of // both strings are same then return true if (i == len1 && j == len2) { return true ; } // if any alphanumeric characters of // both strings are not same then return false else if (str1[i] != str2[j]) { return false ; } // If current character matched, // increase both pointers to // check the next character else { i++; j++; } } // If not same, then return false return false ; } // Function to print Equal or Unequal // if strings are same or not static void CompareAlphanumericUtil(String str1, String str2) { boolean res; // check alphanumeric equality of both strings res = CompareAlphanumeric(str1.toCharArray(), str2.toCharArray()); // if both are alphanumeric equal, // print Equal if (res == true ) { System.out.println( "Equal" ); } // otherwise print Unequal else { System.out.println( "Unequal" ); } } // Driver code public static void main(String[] args) { String str1, str2; str1 = "Ram, Shyam" ; str2 = " Ram - Shyam." ; CompareAlphanumericUtil(str1, str2); str1 = "abc123" ; str2 = "123abc" ; CompareAlphanumericUtil(str1, str2); } } // This code is contributed by Rajput-Ji |
Python3
# Function to check alphanumeric equality # of both strings def CompareAlphanumeric(str1, str2): # variable declaration i = 0 j = 0 # Length of first string len1 = len (str1) # Length of second string len2 = len (str2) # To check each and every character of both string while (i < = len1 and j < = len2): # If the current character of the first string # is not an alphanumeric character, # increase the pointer i while (i < len1 and (((str1[i] > = 'a' and str1[i] < = 'z' ) or (str1[i] > = 'A' and str1[i] < = 'Z' ) or (str1[i] > = '0' and str1[i] < = '9' )) = = False )): i + = 1 # If the current character of the second string # is not an alphanumeric character, # increase the pointer j while (j < len2 and (((str2[j] > = 'a' and str2[j] < = 'z' ) or (str2[j] > = 'A' and str2[j] < = 'Z' ) or (str2[j] > = '0' and str2[j] < = '9' )) = = False )): j + = 1 # if all alphanumeric characters of # both strings are same, then return true if (i = = len1 and j = = len2): return True # if any alphanumeric characters of # both strings are not same, then return false elif (str1[i] ! = str2[j]): return False # If current character matched, # increase both pointers # to check the next character else : i + = 1 j + = 1 # If not same, then return false return False # Function to print Equal or Unequal # if strings are same or not def CompareAlphanumericUtil(str1, str2): # check alphanumeric equality of both strings res = CompareAlphanumeric(str1, str2) # if both are alphanumeric equal, print Equal if (res = = True ): print ( "Equal" ) # otherwise print Unequal else : print ( "Unequal" ) # Driver code if __name__ = = '__main__' : str1 = "Ram, Shyam" str2 = " Ram - Shyam." CompareAlphanumericUtil(str1, str2) str1 = "abc123" str2 = "123abc" CompareAlphanumericUtil(str1, str2) # This code is contributed by Surendra_Gangwar |
C#
// C# implementation of the approach using System; class GFG { // Function to check alphanumeric // equality of both strings static bool CompareAlphanumeric( char []str1, char []str2) { // variable declaration int i, j; i = 0; j = 0; // Length of first string int len1 = str1.Length; // Length of second string int len2 = str2.Length; // To check each and every characters // of both string while (i <= len1 && j <= len2) { // If the current character of the first // string is not an alphanumeric character, // increase the pointer i while (i < len1 && (!((str1[i] >= 'a' && str1[i] <= 'z' ) || (str1[i] >= 'A' && str1[i] <= 'Z' ) || (str1[i] >= '0' && str1[i] <= '9' )))) { i++; } // If the current character of the second // string is not an alphanumeric character, // increase the pointer j while (j < len2 && (!((str2[j] >= 'a' && str2[j] <= 'z' ) || (str2[j] >= 'A' && str2[j] <= 'Z' ) || (str2[j] >= '0' && str2[j] <= '9' )))) { j++; } // if all alphanumeric characters of // both strings are same then return true if (i == len1 && j == len2) { return true ; } // if any alphanumeric characters of // both strings are not same then return false else if (str1[i] != str2[j]) { return false ; } // If current character matched, // increase both pointers to // check the next character else { i++; j++; } } // If not same, then return false return false ; } // Function to print Equal or Unequal // if strings are same or not static void CompareAlphanumericUtil( string str1, string str2) { bool res; // check alphanumeric equality of both strings res = CompareAlphanumeric(str1.ToCharArray(), str2.ToCharArray()); // if both are alphanumeric equal, // print Equal if (res == true ) { Console.WriteLine( "Equal" ); } // otherwise print Unequal else { Console.WriteLine( "Unequal" ); } } // Driver code public static void Main() { string str1, str2; str1 = "Ram, Shyam" ; str2 = " Ram - Shyam." ; CompareAlphanumericUtil(str1, str2); str1 = "abc123" ; str2 = "123abc" ; CompareAlphanumericUtil(str1, str2); } } // This code is contributed by AnkitRai01 |
Javascript
<script> // JavaScript implementation of the approach // Function to check alphanumeric // equality of both strings function CompareAlphanumeric(str1, str2) { // variable declaration let i, j; i = 0; j = 0; // Length of first string let len1 = str1.length; // Length of second string let len2 = str2.length; // To check each and every characters // of both string while (i <= len1 && j <= len2) { // If the current character of the first // string is not an alphanumeric character, // increase the pointer i while (i < len1 && (!((str1[i].charCodeAt() >= 'a' .charCodeAt() && str1[i].charCodeAt() <= 'z' .charCodeAt()) || (str1[i].charCodeAt() >= 'A' .charCodeAt() && str1[i].charCodeAt() <= 'Z' .charCodeAt()) || (str1[i].charCodeAt() >= '0' .charCodeAt() && str1[i].charCodeAt() <= '9' .charCodeAt())))) { i++; } // If the current character of the second // string is not an alphanumeric character, // increase the pointer j while (j < len2 && (!((str2[j].charCodeAt() >= 'a' .charCodeAt() && str2[j].charCodeAt() <= 'z' .charCodeAt()) || (str2[j].charCodeAt() >= 'A' .charCodeAt() && str2[j].charCodeAt() <= 'Z' .charCodeAt()) || (str2[j].charCodeAt() >= '0' .charCodeAt() && str2[j].charCodeAt() <= '9' .charCodeAt())))) { j++; } // if all alphanumeric characters of // both strings are same then return true if (i == len1 && j == len2) { return true ; } // if any alphanumeric characters of // both strings are not same then return false else if (str1[i] != str2[j]) { return false ; } // If current character matched, // increase both pointers to // check the next character else { i++; j++; } } // If not same, then return false return false ; } // Function to print Equal or Unequal // if strings are same or not function CompareAlphanumericUtil(str1, str2) { let res; // check alphanumeric equality of both strings res = CompareAlphanumeric(str1.split( '' ), str2.split( '' )); // if both are alphanumeric equal, // print Equal if (res == true ) { document.write( "Equal" + "</br>" ); } // otherwise print Unequal else { document.write( "Unequal" ); } } let str1, str2; str1 = "Ram, Shyam" ; str2 = " Ram - Shyam." ; CompareAlphanumericUtil(str1, str2); str1 = "abc123" ; str2 = "123abc" ; CompareAlphanumericUtil(str1, str2); </script> |
Equal Unequal
Time Complexity: O(n*n)
Auxiliary Space: O(1), as no extra space is required