Longest common anagram subsequence from N strings
Given N strings. Find the longest possible subsequence from each of these N strings such that they are anagram to each other. The task is to print the lexicographically largest subsequence among all the subsequences.
Examples:
Input: s[] = { geeks, esrka, efrsk }
Output: ske
First string has “eks”, Second string has “esk”, third string has “esk”. These three are anagrams. “ske” is lexoigrapically large.Input: string s[] = { loop, lol, olive }
Output: ol
Approach :
- Make a 2-D array of n*26 to store the frequency of each character in string.
- After making frequency array, traverse in reverse direction for each digit and find the string which has the minimum characters of this type.
- After complete reverse traversal, print the character that occurs the minimum number of times since it gives the lexicographically largest string.
Below is the implementation of the above approach.
C++
// C++ program to find longest possible // subsequence anagram of N strings. #include <bits/stdc++.h> using namespace std; const int MAX_CHAR = 26; // function to store frequency of // each character in each string void frequency(int fre[][MAX_CHAR], string s[], int n) { for (int i = 0; i < n; i++) { string str = s[i]; for (int j = 0; j < str.size(); j++) fre[i][str[j] - 'a']++; } } // function to Find longest possible sequence of N // strings which is anagram to each other void LongestSequence(int fre[][MAX_CHAR], int n) { // to get lexicographical largest sequence. for (int i = MAX_CHAR-1; i >= 0; i--) { // find minimum of that character int mi = fre[0][i]; for (int j = 1; j < n; j++) mi = min(fre[j][i], mi); // print that character // minimum number of times while (mi--) cout << (char)('a' + i); } } // Driver code int main() { string s[] = { "loo", "lol", "olive" }; int n = sizeof(s)/sizeof(s[0]); // to strore frequency of each character in each string int fre[n][26] = { 0 }; // to get frequency of each character frequency(fre, s, n); // function call LongestSequence(fre, n); return 0; } |
Java
// Java program to find longest // possible subsequence anagram // of N strings. class GFG { final int MAX_CHAR = 26; // function to store frequency // of each character in each // string static void frequency(int fre[][], String s[], int n) { for (int i = 0; i < n; i++) { String str = s[i]; for (int j = 0; j < str.length(); j++) fre[i][str.charAt(j) - 'a']++; } } // function to Find longest // possible sequence of N // strings which is anagram // to each other static void LongestSequence(int fre[][], int n) { // to get lexicographical // largest sequence. for (int i = 24; i >= 0; i--) { // find minimum of // that character int mi = fre[0][i]; for (int j = 1; j < n; j++) mi = Math.min(fre[j][i], mi); // print that character // minimum number of times while (mi--!=0) System.out.print((char)('a' + i)); } } // Driver code public static void main(String args[]) { String s[] = { "loo", "lol", "olive" }; int n = s.length; // to strore frequency of each // character in each string int fre[][] = new int[n][26] ; // to get frequency // of each character frequency(fre, s, n); // function call LongestSequence(fre, n); } } // This code is contributed // by Arnab Kundu |
Python3
# Python3 program to find longest possible # subsequence anagram of N strings. # Function to store frequency of # each character in each string def frequency(fre, s, n): for i in range(0, n): string = s[i] for j in range(0, len(string)): fre[i][ord(string[j]) - ord('a')] += 1 # Function to Find longest possible sequence # of N strings which is anagram to each other def LongestSequence(fre, n): # to get lexicographical largest sequence. for i in range(MAX_CHAR-1, -1, -1): # find minimum of that character mi = fre[0][i] for j in range(1, n): mi = min(fre[j][i], mi) # print that character # minimum number of times while mi: print(chr(ord('a') + i), end = "") mi -= 1 # Driver code if __name__ == "__main__": s = ["loo", "lol", "olive"] n = len(s) MAX_CHAR = 26 # to strore frequency of each # character in each string fre = [[0 for i in range(26)] for j in range(n)] # To get frequency of each character frequency(fre, s, n) # Function call LongestSequence(fre, n) # This code is contributed by # Rituraj Jain |
C#
// c# program to find longest // possible subsequence anagram // of N strings. using System; class GFG { public readonly int MAX_CHAR = 26; // function to store frequency // of each character in each // string public static void frequency(int[,] fre, string[] s, int n) { for (int i = 0; i < n; i++) { string str = s[i]; for (int j = 0; j < str.Length; j++) { fre[i, str[j] - 'a']++; } } } // function to Find longest // possible sequence of N // strings which is anagram // to each other public static void LongestSequence(int[, ] fre, int n) { // to get lexicographical // largest sequence. for (int i = 24; i >= 0; i--) { // find minimum of // that character int mi = fre[0, i]; for (int j = 1; j < n; j++) { mi = Math.Min(fre[j, i], mi); } // print that character // minimum number of times while (mi--!=0) { Console.Write((char)('a' + i)); } } } // Driver code public static void Main(string[] args) { string[] s = new string[] {"loo", "lol", "olive"}; int n = s.Length; // to strore frequency of each // character in each string int[, ] fre = new int[n, 26]; // to get frequency // of each character frequency(fre, s, n); // function call LongestSequence(fre, n); } } // This code is contributed by Shrikanth13 |
Output:
ol
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