Power Set in Lexicographic order
This article is about generating Power set in lexicographical order.
Examples :
Input : abc Output : a ab abc ac b bc c
The idea is to sort array first. After sorting, one by one fix characters and recursively generates all subsets starting from them. After every recursive call, we remove last character so that next permutation can be generated.
C++
// CPP program to generate power set in // lexicographic order. #include <bits/stdc++.h> using namespace std; // str : Stores input string // n : Length of str. // curr : Stores current permutation // index : Index in current permutation, curr void permuteRec(string str, int n, int index = -1, string curr = "") { // base case if (index == n) return; cout << curr << "\n"; for (int i = index + 1; i < n; i++) { curr += str[i]; permuteRec(str, n, i, curr); // backtracking curr = curr.erase(curr.size() - 1); } return; } // Generates power set in lexicographic // order. void powerSet(string str) { sort(str.begin(), str.end()); permuteRec(str, str.size()); } // Driver code int main() { string str = "cab"; powerSet(str); return 0; } |
chevron_right
filter_none
Java
// Java program to generate power set in // lexicographic order. import java.util.*; class GFG { // str : Stores input string // n : Length of str. // curr : Stores current permutation // index : Index in current permutation, curr static void permuteRec(String str, int n, int index, String curr) { // base case if (index == n) { return; } System.out.println(curr); for (int i = index + 1; i < n; i++) { curr += str.charAt(i); permuteRec(str, n, i, curr); // backtracking curr = curr.substring(0, curr.length() - 1); } return; } // Generates power set in lexicographic // order. static void powerSet(String str) { char[] arr = str.toCharArray(); Arrays.sort(arr); permuteRec(new String(arr), str.length(), -1, ""); } // Driver code public static void main(String[] args) { String str = "cab"; powerSet(str); } } /* This code contributed by PrinciRaj1992 */ |
chevron_right
filter_none
Python3
# Python3 program to generate power # set in lexicographic order. # str : Stores input string # n : Length of str. # curr : Stores current permutation # index : Index in current permutation, curr def permuteRec(string, n, index = -1, curr = ""): # base case if index == n: return if len(curr) > 0: print(curr) for i in range(index + 1, n): curr += string[i] permuteRec(string, n, i, curr) # backtracking curr = curr[:len(curr) - 1] # Generates power set in lexicographic order def powerSet(string): string = ''.join(sorted(string)) permuteRec(string, len(string)) # Driver Code if __name__ == "__main__": string = "cab" powerSet(string) # This code is contributed by vibhu4agarwal |
chevron_right
filter_none
C#
// C# program to generate power set in // lexicographic order. using System; class GFG { // str : Stores input string // n : Length of str. // curr : Stores current permutation // index : Index in current permutation, curr static void permuteRec(String str, int n, int index, String curr) { // base case if (index == n) { return; } Console.WriteLine(curr); for (int i = index + 1; i < n; i++) { curr += str[i]; permuteRec(str, n, i, curr); // backtracking curr = curr.Substring(0, curr.Length - 1); } return; } // Generates power set in lexicographic // order. static void powerSet(String str) { char[] arr = str.ToCharArray(); Array.Sort(arr); permuteRec(new String(arr), str.Length, -1, ""); } // Driver code public static void Main(String[] args) { String str = "cab"; powerSet(str); } } // This code contributed by Rajput-Ji |
chevron_right
filter_none
PHP
<?php // PHP program to generate power // set in lexicographic order. // str : Stores input string // n : Length of str. // curr : Stores current permutation // index : Index in current permutation, curr function permuteRec($str, $n, $index = -1, $curr = "") { // base case if ($index == $n) return; echo $curr."\n"; for ($i = $index + 1; $i < $n; $i++) { $curr=$curr.$str[$i]; permuteRec($str, $n, $i, $curr); // backtracking $curr =""; } return; } // Generates power set in lexicographic // order. function powerSet($str) { $str = str_split($str); sort($str); permuteRec($str, sizeof($str)); } // Driver code $str = "cab"; powerSet($str); // This code is contributed by Mithun Kumar ?> |
chevron_right
filter_none
Output :
a ab abc ac b bc c
Recommended Posts:
- Print all permutations in sorted (lexicographic) order
- Find a string in lexicographic order which is in between given two strings
- Print a number as string of 'A' and 'B' in lexicographic order
- Generating distinct subsequences of a given string in lexicographic order
- Lexicographic rank of a string using STL
- Lexicographic rank of a string
- Lexicographic rank of a string with duplicate characters
- Find sub-string with given power
- Program for power of a complex number in O(log n)
- Given two numbers as strings, find if one is a power of other
- Recursive program to generate power set
- Highest power of 2 less than or equal to given number
- Decimal to Binary using recursion and without using power operator
- Minimum number of sub-strings of a string such that all are power of 5
- Breaking a number such that first part is integral division of second by a power of 10
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.
