# Find the resultant String after replacing X with Y and removing Z

Given a string str, the task is to replace all occurrences of the given X with given Y and also remove any occurrances of the given Z if present in it with no extra space

Examples:

Input: str = “batman”, X = ‘a’, Y = ‘d’, Z = ‘b’
Output: ntdmd

Input: str = “abba”, X = ‘a’, Y = ‘d’, Z = ‘b’
Output: dd

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach:

• The idea is based on the 2 pointers.
• Let two-variable start and end points to the beginning and end of the string.
• Now if the character at the start is Z, replace it with a character not having Y at another pointer pointing to a location > start keeping in mind to replace character X with Y if found.

Below is the implementation of the above approach:

## C++

 // C++ program to find the resultant String // after replacing X with Y and removing Z    #include using namespace std;    // Function to replace and remove void replaceRemove(string& s, char X, char Y, char Z) {        // Two pointer start and end points     // to beginning and end position in the string     int start = 0, end = s.size() - 1;        while (start <= end) {            // If start is having Z         // find X pos in end and         // replace Z with another character         if (s[start] == Z) {                // Find location for having             // different character             // insted of Z             while (end >= 0 && s[end] == Z) {                 end--;             }                // If found swap character             // at start and end             if (end > start) {                 swap(s[start], s[end]);                 if (s[start] == X)                     s[start] = Y;                 start++;             }         }         // Else increment start         // Also checkin for X         // at start position         else {             if (s[start] == X)                 s[start] = Y;             start++;         }     }     while (s.size() > 0 && s[s.size() - 1] == Z) {         s.pop_back();     } }    // Driver code int main() {        string str = "batman";     char X = 'a', Y = 'd', Z = 'b';        replaceRemove(str, X, Y, Z);        if (str.size() == 0) {         cout << -1;     }     else {         cout << str;     }        return 0; }

## Java

 // Java program to find the resultant String  // after replacing X with Y and removing Z  class GFG {            // Function to replace and remove      static String replaceRemove(char []s, char X,                                     char Y, char Z)      {                 // Two pointer start and end points          // to beginning and end position in the string          int start = 0, end = s.length - 1;                 while (start <= end)         {                     // If start is having Z              // find X pos in end and              // replace Z with another character              if (s[start] == Z)             {                         // Find location for having                  // different character                  // insted of Z                  while (end >= 0 && s[end] == Z)                  {                      end--;                  }                         char temp ;                                    // If found swap character                  // at start and end                  if (end > start)                  {                      temp = s[start];                     s[start] = s[end];                     s[end] = temp;                                            if (s[start] == X)                          s[start] = Y;                      start++;                  }              }                             // Else increment start              // Also checkin for X              // at start position              else              {                  if (s[start] == X)                      s[start] = Y;                  start++;              }          }                     String new_s = new String(s);         while (new_s.length() > 0 &&              new_s.charAt(new_s.length() - 1) == Z)          {              new_s = new_s.substring(0,new_s.length() - 1);          }          return new_s;     }             // Driver code      public static void main (String[] args)      {                 String str = "batman";          char X = 'a', Y = 'd', Z = 'b';                 str = replaceRemove(str.toCharArray() , X, Y, Z);                 if (str.length() == 0)         {              System.out.println(-1);          }          else         {              System.out.println(str);          }      }  }    // This code is contributed by AnkitRai01

## Python3

 # Python3 program to find the resultant String  # after replacing X with Y and removing Z     # Function to replace and remove  def replaceRemove(s, X, Y, Z) :        s = list(s);            # Two pointer start and end points     # to beginning and end position in the string     start = 0;     end = len(s) - 1;            while (start <= end) :                    # If start is having Z         # find X pos in end and         # replace Z with another character         if (s[start] == Z) :                            # Find location for having             # different character             # insted of Z              while (end >= 0 and s[end] == Z) :                 end -= 1;                                # If found swap character              # at start and end             if (end > start) :                 s[start], s[end] = s[end], s[start]                 if (s[start] == X):                     s[start] = Y;                                        start += 1                            # Else increment start         # Also checkin for X         # at start position         else :             if (s[start] == X) :                 s[start] = Y;                                start += 1;                    while (len(s) > 0 and s[len(s) - 1] == Z):         s.pop();                return "".join(s)    # Driver code  if __name__ == "__main__" :         string = "batman";      X = 'a'; Y = 'd'; Z = 'b';         string = replaceRemove(string, X, Y, Z);         if (len(string) == 0) :         print(-1);         else :         print(string);     # This code is contributed by AnkitRai01

## C#

 // C# program to find the resultant String  // after replacing X with Y and removing Z  using System;    class GFG {            // Function to replace and remove      static String replaceRemove(char []s, char X,                                  char Y, char Z)      {                 // Two pointer start and end points          // to beginning and end position in the string          int start = 0, end = s.Length - 1;                 while (start <= end)         {                     // If start is having Z              // find X pos in end and              // replace Z with another character              if (s[start] == Z)             {                         // Find location for having                  // different character                  // insted of Z                  while (end >= 0 && s[end] == Z)                  {                      end--;                  }                         char temp ;                                    // If found swap character                  // at start and end                  if (end > start)                  {                      temp = s[start];                     s[start] = s[end];                     s[end] = temp;                                            if (s[start] == X)                          s[start] = Y;                      start++;                  }              }                             // Else increment start              // Also checkin for X              // at start position              else             {                  if (s[start] == X)                      s[start] = Y;                  start++;              }          }                     String new_s = new String(s);         while (new_s.Length > 0 &&                 new_s[new_s.Length - 1] == Z)          {              new_s = new_s.Substring(0,new_s.Length - 1);          }          return new_s;     }             // Driver code      public static void Main(String[] args)      {                 String str = "batman";          char X = 'a', Y = 'd', Z = 'b';                 str = replaceRemove(str.ToCharArray() , X, Y, Z);                 if (str.Length == 0)         {              Console.WriteLine(-1);          }          else         {              Console.WriteLine(str);          }      }  }    // This code is contributed by PrinciRaj1992

Output :

ndtmd

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Improved By : AnkitRai01, princiraj1992