Given a string, find all possible palindromic partitions of given string.
Example:
Note that this problem is different from Palindrome Partitioning Problem, there the task was to find the partitioning with minimum cuts in input string. Here we need to print all possible partitions.
The idea is to go through every substring starting from first character, check if it is palindrome. If yes, then add the substring to solution and recur for remaining part. Below is complete algorithm.
Below is the implementation of above idea.
C++
// C++ program to print all palindromic partitions of a given string #include<bits/stdc++.h> using namespace std; // A utility function to check if str is palindroem bool isPalindrome(string str, int low, int high) { while (low < high) { if (str[low] != str[high]) return false; low++; high--; } return true; } // Recursive function to find all palindromic partitions of str[start..n-1] // allPart --> A vector of vector of strings. Every vector inside it stores // a partition // currPart --> A vector of strings to store current partition void allPalPartUtil(vector<vector<string> >&allPart, vector<string> &currPart, int start, int n, string str) { // If 'start' has reached len if (start >= n) { allPart.push_back(currPart); return; } // Pick all possible ending points for substrings for (int i=start; i<n; i++) { // If substring str[start..i] is palindrome if (isPalindrome(str, start, i)) { // Add the substring to result currPart.push_back(str.substr(start, i-start+1)); // Recur for remaining remaining substring allPalPartUtil(allPart, currPart, i+1, n, str); // Remove substring str[start..i] from current // partition currPart.pop_back(); } } } // Function to print all possible palindromic partitions of // str. It mainly creates vectors and calls allPalPartUtil() void allPalPartitions(string str) { int n = str.length(); // To Store all palindromic partitions vector<vector<string> > allPart; // To store current palindromic partition vector<string> currPart; // Call recursive function to generate all partiions // and store in allPart allPalPartUtil(allPart, currPart, 0, n, str); // Print all partitions generated by above call for (int i=0; i< allPart.size(); i++ ) { for (int j=0; j<allPart[i].size(); j++) cout << allPart[i][j] << " "; cout << "\n"; } } // Driver program int main() { string str = "nitin"; allPalPartitions(str); return 0; } |
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Java
// Java program to print all palindromic // partitions of a given string import java.util.ArrayList; import java.util.Deque; import java.util.LinkedList; public class PrintAllPalindrome { // Driver program public static void main(String[] args) { String input = "nitin"; System.out.println("All possible palindrome" + "partions for " + input + " are :"); allPalPartitions(input); } // Function to print all possible // palindromic partitions of str. // It mainly creates vectors and // calls allPalPartUtil() private static void allPalPartitions(String input) { int n = input.length(); // To Store all palindromic partitions ArrayList<ArrayList<String>> allPart = new ArrayList<>(); // To store current palindromic partition Deque<String> currPart = new LinkedList<String>(); // Call recursive function to generate // all partiions and store in allPart allPalPartitonsUtil(allPart, currPart, 0, n, input); // Print all partitions generated by above call for (int i = 0; i < allPart.size(); i++) { for (int j = 0; j < allPart.get(i).size(); j++) { System.out.print(allPart.get(i).get(j) + " "); } System.out.println(); } } // Recursive function to find all palindromic // partitions of input[start..n-1] allPart --> A // ArrayList of Deque of strings. Every Deque // inside it stores a partition currPart --> A // Deque of strings to store current partition private static void allPalPartitonsUtil(ArrayList<ArrayList<String>> allPart, Deque<String> currPart, int start, int n, String input) { // If 'start' has reached len if (start >= n) { allPart.add(new ArrayList<>(currPart)); return; } // Pick all possible ending points for substrings for (int i = start; i < n; i++) { // If substring str[start..i] is palindrome if (isPalindrome(input, start, i)) { // Add the substring to result currPart.addLast(input.substring(start, i + 1)); // Recur for remaining remaining substring allPalPartitonsUtil(allPart, currPart, i + 1, n, input); // Remove substring str[start..i] from current // partition currPart.removeLast(); } } } // A utility function to check // if input is Palindrome private static boolean isPalindrome(String input, int start, int i) { while (start < i) { if (input.charAt(start++) != input.charAt(i--)) return false; } return true; } } // This code is contributed by Prerna Saini |
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Python3
# Python3 program to print all # palindromic partitions of a given string # A utility function to check if # str is palindrome def isPalindrome(string: str, low: int, high: int): while low < high: if string[low] != string[high]: return False low += 1 high -= 1 return True # Recursive function to find all # palindromic partitions of str[start..n-1] # allPart --> A vector of vector of strings. # Every vector inside it stores a partition # currPart --> A vector of strings to store current partition def allPalPartUtil(allPart: list, currPart: list, start: int, n: int, string: str): # If 'start' has reached len if start >= n: # In Python list are passed by reference # that is why it is needed to copy first # and then append x = currPart.copy() allPart.append(x) return # Pick all possible ending points for substrings for i in range(start, n): # If substring str[start..i] is palindrome if isPalindrome(string, start, i): # Add the substring to result currPart.append(string[start:i + 1]) # Recur for remaining remaining substring allPalPartUtil(allPart, currPart, i + 1, n, string) # Remove substring str[start..i] # from current partition currPart.pop() # Function to print all possible # palindromic partitions of str. # It mainly creates vectors and # calls allPalPartUtil() def allPalPartitions(string: str): n = len(string) # To Store all palindromic partitions allPart = [] # To store current palindromic partition currPart = [] # Call recursive function to generate # all partitions and store in allPart allPalPartUtil(allPart, currPart, 0, n, string) # Print all partitions generated by above call for i in range(len(allPart)): for j in range(len(allPart[i])): print(allPart[i][j], end = " ") print() # Driver Code if __name__ == "__main__": string = "nitin" allPalPartitions(string) # This code is contributed by # sanjeev2552 |
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C#
// C# program to print all palindromic // partitions of a given string using System; using System.Collections.Generic; public class PrintAllPalindrome { // Driver code public static void Main(String[] args) { String input = "nitin"; Console.WriteLine("All possible palindrome" + "partions for " + input + " are :"); allPalPartitions(input); } // Function to print all possible // palindromic partitions of str. // It mainly creates vectors and // calls allPalPartUtil() private static void allPalPartitions(String input) { int n = input.Length; // To Store all palindromic partitions List<List<String>> allPart = new List<List<String>>(); // To store current palindromic partition List<String> currPart = new List<String>(); // Call recursive function to generate // all partiions and store in allPart allPalPartitonsUtil(allPart, currPart, 0, n, input); // Print all partitions generated by above call for (int i = 0; i < allPart.Count; i++) { for (int j = 0; j < allPart[i].Count; j++) { Console.Write(allPart[i][j] + " "); } Console.WriteLine(); } } // Recursive function to find all palindromic // partitions of input[start..n-1] allPart --> A // List of Deque of strings. Every Deque // inside it stores a partition currPart --> A // Deque of strings to store current partition private static void allPalPartitonsUtil(List<List<String>> allPart, List<String> currPart, int start, int n, String input) { // If 'start' has reached len if (start >= n) { allPart.Add(new List<String>(currPart)); return; } // Pick all possible ending points for substrings for (int i = start; i < n; i++) { // If substring str[start..i] is palindrome if (isPalindrome(input, start, i)) { // Add the substring to result currPart.Add(input.Substring(start, i + 1 - start)); // Recur for remaining remaining substring allPalPartitonsUtil(allPart, currPart, i + 1, n, input); // Remove substring str[start..i] from current // partition currPart.RemoveAt(currPart.Count - 1); } } } // A utility function to check // if input is Palindrome private static bool isPalindrome(String input, int start, int i) { while (start < i) { if (input[start++] != input[i--]) return false; } return true; } } // This code is contributed by PrinciRaj1992 |
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Output:
n i t i n n iti n nitin
This article is contributed by Ekta Goel. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.
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