Print all permutations of a string keeping the sequence but changing cases.
Examples:
Input : ab Output : AB Ab ab aB Input : ABC Output : abc Abc aBc ABc abC AbC aBC ABC
Method 1 (Naive) : Naive approach would be to traverse the whole string and for every character, consider two cases, (1) change case and recur (2) Do not change case and recur.
Method 2 (Better) For a string of length n there exists 2n maximum combinations. We can represent this as a bitwise operation.
The same idea is discussed in Print all subsequences.
Below is the implementation of above idea :
C++
// CPP code to print all permutations // with respect to cases #include <bits/stdc++.h> using namespace std; // Function to generate permutations void permute(string input) { int n = input.length(); // Number of permutations is 2^n int max = 1 << n; // Converting string to lower case transform(input.begin(), input.end(), input.begin(), ::tolower); // Using all subsequences and permuting them for (int i = 0; i < max; i++) { // If j-th bit is set, we convert it to upper case string combination = input; for (int j = 0; j < n; j++) if (((i >> j) & 1) == 1) combination[j] = toupper(input.at(j)); // Printing current combination cout << combination << " "; } } // Driver code int main() { permute("ABC"); return 0; } |
Java
// Java program to print all permutations // with respect to cases public class PermuteString { // Function to generate permutations static void permute(String input) { int n = input.length(); // Number of permutations is 2^n int max = 1 << n; // Converting string to lower case input = input.toLowerCase(); // Using all subsequences and permuting them for(int i = 0;i < max; i++) { char combination[] = input.toCharArray(); // If j-th bit is set, we convert it to upper case for(int j = 0; j < n; j++) { if(((i >> j) & 1) == 1) combination[j] = (char) (combination[j]-32); } // Printing current combination System.out.print(combination); System.out.print(" "); } } // Driver Program to test above function public static void main(String[] args) { permute("ABC"); } } // This code is contributed by Sumit Ghosh |
Python
# Python code to print all permutations # with respect to cases # Function to generate permutations def permute(inp): n = len(inp) # Number of permutations is 2^n mx = 1 << n # Converting string to lower case inp = inp.lower() # Using all subsequences and permuting them for i in range(mx): # If j-th bit is set, we convert it to upper case combination = [k for k in inp] for j in range(n): if (((i >> j) & 1) == 1): combination[j] = inp[j].upper() temp = "" # Printing current combination for i in combination: temp += i print temp, # Driver code permute("ABC") # This code is contributed by Sachin Bisht |
C#
// C# program to print all permutations // with respect to cases using System; class PermuteString { // Function to generate // permutations static void permute(String input) { int n = input.Length; // Number of permutations is 2^n int max = 1 << n; // Converting string // to lower case input = input.ToLower(); // Using all subsequences // and permuting them for(int i = 0;i < max; i++) { char []combination = input.ToCharArray(); // If j-th bit is set, we // convert it to upper case for(int j = 0; j < n; j++) { if(((i >> j) & 1) == 1) combination[j] = (char) (combination[j] - 32); } // Printing current combination Console.Write(combination); Console.Write(" "); } } // Driver Code public static void Main() { permute("ABC"); } } // This code is contributed by Nitin Mittal. |
PHP
<?php // PHP program to print all permutations // with respect to cases // Function to generate permutations function permute($input) { $n = strlen($input); // Number of permutations is 2^n $max = 1 << $n; // Converting string to lower case $input = strtolower($input); // Using all subsequences and permuting them for($i = 0; $i < $max; $i++) { $combination = $input; // If j-th bit is set, we convert // it to upper case for($j = 0; $j < $n; $j++) { if((($i >> $j) & 1) == 1) $combination[$j] = chr(ord($combination[$j]) - 32); } // Printing current combination echo $combination . " "; } } // Driver Code permute("ABC"); // This code is contributed by mits ?> |
Output:
abc Abc aBc ABc abC AbC aBC ABC
Asked in : Facebook.
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