Given a string str that may contain one more occurrences of “AB”. Replace all occurrences of “AB” with “C” in str.
Examples:
Input : str = "helloABworld" Output : str = "helloCworld" Input : str = "fghABsdfABysu" Output : str = "fghCsdfCysu"
A simple solution is to find all occurrences of “AB”. For every occurrence, replace it with C and more all characters one position back.
C++
// C++ program to replace all occurrences of "AB" // with "C" #include <bits/stdc++.h> void translate( char * str) { if (str[0] == '' ) return ; // Start traversing from second character for ( int i=1; str[i] != '' ; i++) { // If previous character is 'A' and // current character is 'B" if (str[i-1]== 'A' && str[i]== 'B' ) { // Replace previous character with // 'C' and move all subsequent // characters one position back str[i-1] = 'C' ; for ( int j=i; str[j]!= '' ; j++) str[j] = str[j+1]; } } return ; } // Driver code int main() { char str[] = "helloABworldABGfG" ; translate(str); printf ( "The modified string is :\n" ); printf ( "%s" , str); } |
Java
// Java program to replace all // occurrences of "AB" with "C" import java.io.*; class GFG { static void translate( char str[]) { // Start traversing from second character for ( int i = 1 ; i < str.length; i++) { // If previous character is 'A' and // current character is 'B" if (str[i - 1 ] == 'A' && str[i] == 'B' ) { // Replace previous character with // 'C' and move all subsequent // characters one position back str[i - 1 ] = 'C' ; int j; for (j = i; j < str.length - 1 ; j++) str[j] = str[j + 1 ]; str[j] = ' ' ; } } return ; } // Driver code public static void main(String args[]) { String st = "helloABworldABGfG" ; char str[] = st.toCharArray(); translate(str); System.out.println( "The modified string is :" ); System.out.println(str); } } // This code is contributed by Nikita Tiwari. |
Python3
# Python 3 program to replace all # occurrences of "AB" with "C" def translate(st) : # Start traversing from second character for i in range ( 1 , len (st)) : # If previous character is 'A' # and current character is 'B" if (st[i - 1 ] = = 'A' and st[i] = = 'B' ) : # Replace previous character with # 'C' and move all subsequent # characters one position back st[i - 1 ] = 'C' for j in range (i, len (st) - 1 ) : st[j] = st[j + 1 ] st[ len (st) - 1 ] = ' ' return # Driver code st = list ( "helloABworldABGfG" ) translate(st) print ( "The modified string is :" ) print (''.join(st)) # This code is contributed by Nikita Tiwari. |
C#
// C# program to replace all // occurrences of "AB" with "C" using System; class GFG { static void translate( char []str) { // Start traversing from second character for ( int i = 1; i < str.Length; i++) { // If previous character is 'A' and // current character is 'B" if (str[i - 1] == 'A' && str[i] == 'B' ) { // Replace previous character with // 'C' and move all subsequent // characters one position back str[i - 1] = 'C' ; int j; for (j = i; j < str.Length - 1; j++) str[j] = str[j + 1]; str[j] = ' ' ; } } return ; } // Driver code public static void Main() { String st = "helloABworldABGfG" ; char []str = st.ToCharArray(); translate(str); Console.WriteLine( "The modified string is :" ); Console.Write(str); } } // This code is contributed by Nitin Mittal. |
PHP
<?php // PHP program to replace all // occurrences of "AB" with "C" function translate(& $str ) { if ( $str [0] == '' ) return ; // Start traversing from second character for ( $i = 1; $i < strlen ( $str ); $i ++) { // If previous character is 'A' and // current character is 'B" if ( $str [ $i - 1] == 'A' && $str [ $i ] == 'B' ) { // Replace previous character with // 'C' and move all subsequent // characters one position back $str [ $i - 1] = 'C' ; for ( $j = $i ; $j < strlen ( $str ) ; $j ++) $str [ $j ] = $str [ $j + 1]; } } return ; } // Driver code $str = "helloABworldABGfG" ; translate( $str ); echo "The modified string is :\n" ; echo $str ; // This code is contributed // by ChitraNayal ?> |
Output :
The modified string is : helloCworldCGfG
Time Complexity : O(n2)
Auxiliary Space : O(1)
An efficient solution is to keep track of two indexes, one for modified string (i in below code) and other for original string (j in below code). If we find “AB” at current index j, we increment j by 2 and i by 1. Otherwise we increment both and copy character from j to i.
Below is implementation of above idea.
C++
// Efficient C++ program to replace all occurrences // of "AB" with "C" #include <bits/stdc++.h> void translate( char * str) { int len = strlen (str); if (len < 2) return ; int i = 0; // Index in modified string int j = 0; // Index in original string // Traverse string while (j < len-1) { // Replace occurrence of "AB" with "C" if (str[j] == 'A' && str[j+1] == 'B' ) { // Increment j by 2 j = j + 2; str[i++] = 'C' ; continue ; } str[i++] = str[j++]; } if (j == len-1) str[i++] = str[j]; // add a null character to terminate string str[i] = '' ; } // Driver code int main() { char str[] = "helloABworldABGfG" ; translate(str); printf ( "The modified string is :\n" ); printf ( "%s" , str); } |
Java
// Efficient Java program to replace // all occurrences of "AB" with "C" import java.io.*; class GFG { static void translate( char str[]) { int len = str.length; if (len < 2 ) return ; // Index in modified string int i = 0 ; // Index in original string int j = 0 ; // Traverse string while (j < len - 1 ) { // Replace occurrence of "AB" with "C" if (str[j] == 'A' && str[j + 1 ] == 'B' ) { // Increment j by 2 j = j + 2 ; str[i++] = 'C' ; continue ; } str[i++] = str[j++]; } if (j == len - 1 ) str[i++] = str[j]; // add a null character to terminate string str[i] = ' ' ; str[len - 1 ]= ' ' ; } // Driver code public static void main(String args[]) { String st= "helloABworldABGfG" ; char str[] = st.toCharArray(); translate(str); System.out.println( "The modified string is :" ); System.out.println(str); } } // This code is contributed // by Nikita Tiwari. |
Python3
# Python 3 program to replace all # occurrences of "AB" with "C" def translate(st) : l = len (st) if (l < 2 ) : return i = 0 # Index in modified string j = 0 # Index in original string # Traverse string while (j < l - 1 ) : # Replace occurrence of "AB" with "C" if (st[j] = = 'A' and st[j + 1 ] = = 'B' ) : # Increment j by 2 j + = 2 st[i] = 'C' i + = 1 continue st[i] = st[j] i + = 1 j + = 1 if (j = = l - 1 ) : st[i] = st[j] i + = 1 # add a null character to # terminate string st[i] = ' ' st[l - 1 ] = ' ' # Driver code st = list ( "helloABworldABGfG" ) translate(st) print ( "The modified string is :" ) print (''.join(st)) # This code is contributed by Nikita Tiwari. |
C#
// Efficient C# program to replace // all occurrences of "AB" with "C" using System; class GFG { static void translate( char []str) { int len = str.Length; if (len < 2) return ; // Index in modified string int i = 0; // Index in original string int j = 0; // Traverse string while (j < len - 1) { // Replace occurrence of "AB" with "C" if (str[j] == 'A' && str[j + 1] == 'B' ) { // Increment j by 2 j = j + 2; str[i++] = 'C' ; continue ; } str[i++] = str[j++]; } if (j == len - 1) str[i++] = str[j]; // add a null character to // terminate string str[i] = ' ' ; str[len - 1]= ' ' ; } // Driver code public static void Main() { String st= "helloABworldABGfG" ; char []str = st.ToCharArray(); translate(str); Console.Write( "The modified string is :" ); Console.Write(str); } } // This code is contributed by nitin mittal. |
Output:
The modified string is : helloCworldCGfG
Time Complexity : O(n)
Auxiliary Space : O(1)
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