Expand the string according to the given conditions

18 Aug, 2021
Given string str of the type “3(ab)4(cd)”, the task is to expand it to “abababcdcdcdcd” where integers are from the range [1, 9].This problem was asked in ThoughtWorks interview held in October 2018.
Examples: 
Input: str = “3(ab)4(cd)” Output: abababcdcdcdcdInput: str = “2(kl)3(ap)” Output: klklapapap 
Approach: We traverse through the string and wait for a numeric value, num to turn up at position i. As soon as it arrives, we check i + 1 for a ‘(‘. If it’s present, then the program enters into a loop to extract whatever is within ‘(‘ and ‘)’ and concatenate it to an empty string, temp. Later, another loop prints the generated string num number of times. Repeat these steps until the string finishes.
Below is the implementation of the approach: 
C++
Java
Python3
C#
Javascript
// C++ implementation of the approach#include<bits/stdc++.h>using namespace std; // Function to expand and print the given stringvoid expandString(string strin){    string temp = "";    int j;     for (int i = 0; i < strin.length(); i++)    {        if (strin[i] >= 0)        {             // Subtract '0' to convert char to int            int num = strin[i] - '0';            if (strin[i + 1] == '(')            {                 // Characters within brackets                for (j = i + 1; strin[j] != ')'; j++)                {                    if ((strin[j] >= 'a' && strin[j] <= 'z') ||                        (strin[j] >= 'A' && strin[j] <= 'Z'))                    {                        temp += strin[j];                    }                }                 // Expanding                for (int k = 1; k <= num; k++)                {                    cout << (temp);                }                 // Reset the variables                num = 0;                temp = "";                 if (j < strin.length())                {                    i = j;                }            }        }    }} // Driver codeint main(){    string strin = "3(ab)4(cd)";    expandString(strin);} // This code is contributed by Surendra_Gangwar
// Java implementation of the approachpublic class GFG {     // Function to expand and print the given string    static void expandString(String strin)    {        String temp = "";        int j;         for (int i = 0; i < strin.length(); i++) {            if (strin.charAt(i) >= 0) {                 // Subtract '0' to convert char to int                int num = strin.charAt(i) - '0';                if (strin.charAt(i + 1) == '(') {                     // Characters within brackets                    for (j = i + 1; strin.charAt(j) != ')'; j++) {                        if ((strin.charAt(j) >= 'a'                             && strin.charAt(j) <= 'z')                            || (strin.charAt(j) >= 'A'                                && strin.charAt(j) <= 'Z')) {                            temp += strin.charAt(j);                        }                    }                     // Expanding                    for (int k = 1; k <= num; k++) {                        System.out.print(temp);                    }                     // Reset the variables                    num = 0;                    temp = "";                     if (j < strin.length()) {                        i = j;                    }                }            }        }    }     // Driver code    public static void main(String args[])    {        String strin = "3(ab)4(cd)";        expandString(strin);    }}
# Python3 implementation of the approach # Function to expand and print the given stringdef expandString(strin):         temp = ""    j = 0    i = 0    while(i < len(strin)):        if (strin[i] >= "0"):                         # Subtract '0' to convert char to int            num = ord(strin[i])-ord("0")            if (strin[i + 1] == '('):                                 # Characters within brackets                j = i + 1                while(strin[j] != ')'):                    if ((strin[j] >= 'a' and strin[j] <= 'z') or \                        (strin[j] >= 'A' and strin[j] <= 'Z')):                        temp += strin[j]                    j += 1                                     # Expanding                for k in range(1, num + 1):                    print(temp,end="")                                     # Reset the variables                num = 0                temp = ""                if (j < len(strin)):                    i = j        i += 1 # Driver codestrin = "3(ab)4(cd)"expandString(strin) # This code is contributed by shubhamsingh10
// C# implementation of// the above approachusing System;class GFG{ // Function to expand and// print the given stringstatic void expandString(string strin){  string temp = "";  int j;   for (int i = 0;           i < strin.Length; i++)  {    if (strin[i] >= 0)    {      // Subtract '0' to      // convert char to int      int num = strin[i] - '0';      if (strin[i + 1] == '(')      {        // Characters within brackets        for (j = i + 1;             strin[j] != ')'; j++)        {          if ((strin[j] >= 'a' &&               strin[j] <= 'z') ||              (strin[j] >= 'A' &&               strin[j] <= 'Z'))          {            temp += strin[j];          }        }         // Expanding        for (int k = 1; k <= num; k++)        {          Console.Write(temp);        }         // Reset the variables        num = 0;        temp = "";         if (j < strin.Length)        {          i = j;        }      }    }  }} // Driver codepublic static void Main(String [] args){  string strin = "3(ab)4(cd)";  expandString(strin);}} // This code is contributed by Chitranayal
<script>// Javascript implementation of the approach         // Function to expand and print the given string    function expandString(strin)    {        let temp = "";        let j;          for (let i = 0; i < strin.length; i++) {            if (strin[i].charCodeAt(0) >= 0) {                  // Subtract '0' to convert char to int                let num = strin[i].charCodeAt(0) - '0'.charCodeAt(0);                if (strin[i+1] == '(') {                      // Characters within brackets                    for (j = i + 1; strin[j] != ')'; j++) {                        if ((strin[j] >= 'a'                             && strin[j] <= 'z')                            || (strin[j] >= 'A'                                && strin[j] <= 'Z')) {                            temp += strin[j];                        }                    }                      // Expanding                    for (let k = 1; k <= num; k++) {                        document.write(temp);                    }                      // Reset the variables                    num = 0;                    temp = "";                      if (j < strin.length) {                        i = j;                    }                }            }        }    }         // Driver code    let strin = "3(ab)4(cd)";    expandString(strin);  // This code is contributed by rag2127</script>
abababcdcdcdcd
 
Time Complexity: O(N*N)Auxiliary Space: O(1)
SURENDRA_GANGWAR
SHUBHAMSINGH10
Code_Mech
ukasp
rag2127
pankajsharmagfg
Thoughtworks
Algorithms
Strings
Thoughtworks
Strings
Algorithms
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