Given a sequence of words, print all anagrams together using STL
Given an array of words, print all anagrams together.
For example,
Input: array = {“cat”, “dog”, “tac”, “god”, “act”}
output: cat tac act, dog god
Explanation: cat tac and act are anagrams
and dog and god are anagrams as
they have the same set of characters.
Input: array = {“abc”, “def”, “ghi”}
output: abc, def, ghi
Explanation: There are no anagrams in the array.Other approaches are discussed herein these posts:
- given-a-sequence-of-words-print-all-anagrams-together
- given-a-sequence-of-words-print-all-anagrams-together-set-2
Approach: This is a HashMap solution using C++ Standard Template Library which stores the Key-Value Pair. In the hashmap, the key will be the sorted set of characters and value will be the output string. Two anagrams will be similar when their characters are sorted. Now,
- Store the vector elements in HashMap with key as the sorted string.
- If the key is same, then add the string to the value of HashMap(string vector).
- Traverse the HashMap and print the anagram strings.
C++
// C++ program for finding all anagram
// pairs in the given array
#include <algorithm>
#include <iostream>
#include <unordered_map>
#include <vector>
using namespace std;
// Utility function for
// printing anagram list
void printAnagram(unordered_map<string,vector<string> >& store)
{
for (auto it:store)
{
vector<string> temp_vec(it.second);
int size = temp_vec.size();
for (int i = 0; i < size; i++)
cout << temp_vec[i] << " ";
cout << "\n";
}
}
// Utility function for storing
// the vector of strings into HashMap
void storeInMap(vector<string>& vec)
{
unordered_map<string,vector<string> > store;
for (int i = 0; i < vec.size(); i++)
{
string tempString(vec[i]);
// sort the string
sort(tempString.begin(),tempString.end());
// make hash of a sorted string
store[tempString].push_back(vec[i]);
}
// print utility function for printing
// all the anagrams
printAnagram(store);
}
// Driver code
int main()
{
// initialize vector of strings
vector<string> arr;
arr.push_back("geeksquiz");
arr.push_back("geeksforgeeks");
arr.push_back("abcd");
arr.push_back("forgeeksgeeks");
arr.push_back("zuiqkeegs");
arr.push_back("cat");
arr.push_back("act");
arr.push_back("tca");
// utility function for storing
// strings into hashmap
storeInMap(arr);
return 0;
}
Python3
# Python3 program for finding all anagram
# pairs in the given array
from collections import defaultdict
# Utility function for
# printing anagram list
def printAnagram(store: dict) -> None:
for (k, v) in store.items():
temp_vec = v
size = len(temp_vec)
if (size > 1):
for i in range(size):
print(temp_vec[i], end = " ")
print()
# Utility function for storing
# the vector of strings into HashMap
def storeInMap(vec: list) -> None:
store = defaultdict(lambda: list)
for i in range(len(vec)):
tempString = vec[i]
tempString = ''.join(sorted(tempString))
# Check for sorted string
# if it already exists
if (tempString not in store):
temp_vec = []
temp_vec.append(vec[i])
store[tempString] = temp_vec
else:
# Push new string to
# already existing key
temp_vec = store[tempString]
temp_vec.append(vec[i])
store[tempString] = temp_vec
# Print utility function for
# printing all the anagrams
printAnagram(store)
# Driver code
if __name__ == "__main__":
# Initialize vector of strings
arr = []
arr.append("geeksquiz")
arr.append("geeksforgeeks")
arr.append("abcd")
arr.append("forgeeksgeeks")
arr.append("zuiqkeegs")
arr.append("cat")
arr.append("act")
arr.append("tca")
# Utility function for storing
# strings into hashmap
storeInMap(arr)
# This code is contributed by sanjeev2552Note: Compile above program with -std=c++11 flag in g++
Output:
cat act tca geeksforgeeks forgeeksgeeks geeksquiz zuiqkeegs
Complexity Analysis:
- Time Complexity: O(n * m(log m)), where m is the length of a word.
A single traversal through the array is needed. - Space Complexity: O(n).
There are n words in a string. The map requires O(n) space to store the strings.
This article is contributed by Mandeep Singh. If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to review-team@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
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