# Sort the array of strings according to alphabetical order defined by another string

• Difficulty Level : Easy
• Last Updated : 12 Sep, 2022

Given a string str and an array of strings strArr[], the task is to sort the array according to the alphabetical order defined by str

Note: str and every string in strArr[] consists of only lower case alphabets.

Examples:

Input: str = “fguecbdavwyxzhijklmnopqrst”,
strArr[] = {“geeksforgeeks”, “is”, “the”, “best”, “place”, “for”, “learning”}
Output: for geeksforgeeks best is learning place the

Input: str = “avdfghiwyxzjkecbmnopqrstul”,
strArr[] = {“rainbow”, “consists”, “of”, “colours”}
Output: consists colours of rainbow

Approach: Traverse every character of str and store the value in a map with character as the key and its index in the array as the value
Now, this map will act as the new alphabetical order of the characters. Start comparing the string in the strArr[] and instead of comparing the ASCII values of the characters, compare the values mapped to those particular characters in the map i.e. if character c1 appears before character c2 in str then c1 < c2.

Below is the implementation of the above approach:

## C++

 `// C++ implementation of the approach``#include ``using` `namespace` `std;` `// Map to store the characters with their order``// in the new alphabetical order``unordered_map<``char``, ``int``> h;` `// Function that returns true if x < y``// according to the new alphabetical order``bool` `compare(string x, string y)``{``    ``for` `(``int` `i = 0; i < min(x.size(), y.size()); i++) {``        ``if` `(h[x[i]] == h[y[i]])``            ``continue``;``        ``return` `h[x[i]] < h[y[i]];``    ``}``    ``return` `x.size() < y.size();``}` `// Driver code``int` `main()``{``    ``string str = ``"fguecbdavwyxzhijklmnopqrst"``;``    ``vector v{ ``"geeksforgeeks"``, ``"is"``, ``"the"``,``                      ``"best"``, ``"place"``, ``"for"``, ``"learning"` `};` `    ``// Store the order for each character``    ``// in the new alphabetical sequence``    ``h.clear();``    ``for` `(``int` `i = 0; i < str.size(); i++)``        ``h[str[i]] = i;   ` `    ``sort(v.begin(), v.end(), compare);` `    ``// Print the strings after sorting``    ``for` `(``auto` `x : v)``        ``cout << x << ``" "``;``    ` `    ``return` `0;``}`

## Java

 `// Java implementation of the approach``import` `java.util.Arrays;``import` `java.util.Comparator;` `public` `class` `GFG``{``private` `static` `void` `sort(String[] strArr, String str)``{``    ``Comparator myComp = ``new` `Comparator()``    ``{``        ``@Override``        ``public` `int` `compare(String a, String b)``        ``{``            ``for``(``int` `i = ``0``;``                    ``i < Math.min(a.length(),``                                 ``b.length()); i++)``            ``{``                ``if` `(str.indexOf(a.charAt(i)) ==``                    ``str.indexOf(b.charAt(i)))``                ``{``                    ``continue``;``                ``}``                ``else` `if``(str.indexOf(a.charAt(i)) >``                        ``str.indexOf(b.charAt(i)))``                ``{``                    ``return` `1``;``                ``}``                ``else``                ``{``                    ``return` `-``1``;``                ``}``            ``}``            ``return` `0``;``        ``}``    ``};``    ``Arrays.sort(strArr, myComp);``}` `// Driver Code``public` `static` `void` `main(String[] args)``{``    ``String str = ``"fguecbdavwyxzhijklmnopqrst"``;``    ``String[] strArr = {``"geeksforgeeks"``, ``"is"``, ``"the"``, ``"best"``,``                       ``"place"``, ``"for"``, ``"learning"``};``    ` `    ``sort(strArr, str);` `    ``for``(``int` `i = ``0``; i < strArr.length; i++)``    ``{``        ``System.out.print(strArr[i] + ``" "``);``    ``}``}``}`

## Python3

 `# Python3 implementation of the approach` `# Function to sort and print the array``# according to the new alphabetical order``def` `sortStringArray(s, a, n):``    ` `    ``# Sort the array according to the new alphabetical order``    ``a ``=` `sorted``(a, key ``=` `lambda` `word: [s.index(c) ``for` `c ``in` `word])``    ``for` `i ``in` `a:``        ``print``(i, end ``=``' '``)` `# Driver code``s ``=` `"fguecbdavwyxzhijklmnopqrst"``a ``=` `[``"geeksforgeeks"``, ``"is"``, ``"the"``, ``"best"``, ``"place"``, ``"for"``, ``"learning"``]``n ``=` `len``(a)``sortStringArray(s, a, n)`

## Javascript

 ``

Output

`for geeksforgeeks best is learning place the `

Complexity Analysis:

• Time Complexity: O(N * log(N)), where N is the size of the string str
• Auxiliary Space: O(N)

My Personal Notes arrow_drop_up