Generate a string consisting of characters ‘a’ and ‘b’ that satisfy the given conditions
Given two integers A and B, the task is to generate and print a string str such that:
- str must only contain the characters ‘a’ and ‘b’.
- str has length A + B and the occurrence of the character ‘a’ is equal to A and the occurrence of character ‘b’ is equal to B
- The sub-strings “aaa” or “bbb” must not occur in str.
Note: For the given values of A and B, a valid string can always be generated.
Examples:
Input: A = 1, B = 2 Output: abb "abb", "bab" and "bba" are all valid strings.
Input: A = 4, B = 1 Output: aabaa
Approach:
- If occurrence(a) > occurrence(b) then append “aab”
- If occurrence(b) > occurrence(a) then append “bba”
- If occurrence(a) = occurrence(b) then append “ab”
Since we reduce the difference between the occurrences of ‘a’ and ‘b’ by at most 1 in each iteration so “bba” and “aab” are guaranteed not to be followed by “aab” and “bba” respectively.
Below is the implementation of the above approach:
C++
// C++ implementation of the approach#include <bits/stdc++.h>using namespace std;// Function to generate and print the required stringvoid generateString(int A, int B){ string rt; while (0 < A || 0 < B) { // More 'b', append "bba" if (A < B) { if (0 < B--) rt.push_back('b'); if (0 < B--) rt.push_back('b'); if (0 < A--) rt.push_back('a'); } // More 'a', append "aab" else if (B < A) { if (0 < A--) rt.push_back('a'); if (0 < A--) rt.push_back('a'); if (0 < B--) rt.push_back('b'); } // Equal number of 'a' and 'b' // append "ab" else { if (0 < A--) rt.push_back('a'); if (0 < B--) rt.push_back('b'); } } cout << rt;}// Driver codeint main(){ int A = 2, B = 6; generateString(A, B); return 0;} |
Java
// Java implementation of the approachclass GFG{ // Function to generate and // print the required string static void generateString(int A, int B) { String rt = ""; while (0 < A || 0 < B) { // More 'b', append "bba" if (A < B) { if (0 < B--) { rt += ('b'); } if (0 < B--) { rt += ('b'); } if (0 < A--) { rt += ('a'); } } // More 'a', append "aab" else if (B < A) { if (0 < A--) { rt += ('a'); } if (0 < A--) { rt += ('a'); } if (0 < B--) { rt += ('b'); } } // Equal number of 'a' and 'b' // append "ab" else { if (0 < A--) { rt += ('a'); } if (0 < B--) { rt += ('b'); } } } System.out.println(rt); } // Driver code public static void main(String[] args) { int A = 2, B = 6; generateString(A, B); }}// This code is contributed// by PrinciRaj1992 |
Python 3
# Python 3 implementation of the approach# Function to generate and print# the required stringdef generateString(A, B): rt = "" while (0 < A or 0 < B) : # More 'b', append "bba" if (A < B) : if (0 < B): rt = rt +'b' B -= 1 if (0 < B): rt += 'b' B -= 1 if (0 < A): rt += 'a' A -= 1 # More 'a', append "aab" elif (B < A): if (0 < A): rt += 'a' A -= 1 if (0 < A): rt += 'a' A -= 1 if (0 < B): rt += 'b' B -= 1 # Equal number of 'a' and 'b' # append "ab" else : if (0 < A): rt += 'a' A -= 1 if (0 < B): rt += 'b' B -= 1 print(rt)# Driver codeif __name__ == "__main__": A = 2 B = 6 generateString(A, B)# This code is contributed by ita_c |
C#
// C# implementation of the approachusing System;class GFG{ // Function to generate and // print the required string static void generateString(int A, int B) { string rt = ""; while (0 < A || 0 < B) { // More 'b', append "bba" if (A < B) { if (0 < B--) { rt += ('b'); } if (0 < B--) { rt += ('b'); } if (0 < A--) { rt += ('a'); } } // More 'a', append "aab" else if (B < A) { if (0 < A--) { rt += ('a'); } if (0 < A--) { rt += ('a'); } if (0 < B--) { rt += ('b'); } } // Equal number of 'a' and 'b' // append "ab" else { if (0 < A--) { rt += ('a'); } if (0 < B--) { rt += ('b'); } } } Console.WriteLine(rt); } // Driver code public static void Main() { int A = 2, B = 6; generateString(A, B); }}// This code is contributed by Ryuga |
PHP
<?php// PHP implementation of the approach// Function to generate and// print the required stringfunction generateString($A, $B){ $rt = ""; while (0 < $A || 0 < $B) { // More 'b', append "bba" if ($A < $B) { if (0 < $B--) { $rt .= ('b'); } if (0 < $B--) { $rt .= ('b'); } if (0 < $A--) { $rt .= ('a'); } } // More 'a', append "aab" else if ($B < $A) { if (0 < $A--) { $rt .= ('a'); } if (0 < $A--) { $rt .= ('a'); } if (0 < $B--) { $rt .= ('b'); } } // Equal number of 'a' and 'b' // append "ab" else { if (0 < $A--) { $rt .= ('a'); } if (0 < $B--) { $rt .= ('b'); } } } echo($rt);}// Driver code$A = 2; $B = 6;generateString($A, $B);// This code is contributed// by Code Mech?> |
Javascript
<script>// Javascript implementation of the approach // Function to generate and // print the required stringfunction generateString(A,B){ let rt = ""; while (0 < A || 0 < B) { // More 'b', append "bba" if (A < B) { if (0 < B--) { rt += ('b'); } if (0 < B--) { rt += ('b'); } if (0 < A--) { rt += ('a'); } } // More 'a', append "aab" else if (B < A) { if (0 < A--) { rt += ('a'); } if (0 < A--) { rt += ('a'); } if (0 < B--) { rt += ('b'); } } // Equal number of 'a' and 'b' // append "ab" else { if (0 < A--) { rt += ('a'); } if (0 < B--) { rt += ('b'); } } } document.write(rt);}// Driver codelet A = 2, B = 6;generateString(A, B);// This code is contributed by avanitrachhadiya2155</script> |
Output
bbabbabb
Complexity Analysis:
- Time Complexity: O(Max(a,b))
- Auxiliary Space: O(Max(a,b))
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