Given two integers N and K. The task is to print the lexicographically smallest string of length N consisting of lower-case English alphabates such that the sum of the characters of the string equals to K where ‘a’ = 1, ‘b’ = 2, ‘c’ = 3, ….. and ‘z’ = 26.
Examples:
Input: N = 5, K = 42
Output: aaamz
“aaany”, “babmx”, “aablz” etc. are also valid strings
but “aaamz” is the lexicographically smallest.Input: N = 3, K = 25
Output: aaw
Approach:
- Initialize char array of size N and fill all the element by ‘a’.
- Start traversing from the end of the array and replace the elements of the array by ‘z’ if K ≥ 26 or replace it by the character having ASCII value (K + 97 – 1).
- At the same time decrease the value of K by replaced element value i.e. for a = 1, b = 2, c = 3, …, z = 26.
- Also, note that we are subtracting previous element value i.e. (total ‘a’) before current element and adding the same before the end of for loop.
- Check for K < 0 condition and break the for loop.
- Return the new string formed by the elements of the char array as the answer.
Below is the implementation of the above approach:
C++
// C++ implementation of the approach #include<bits/stdc++.h> using namespace std; // Function to return the lexicographically // smallest string of length n that // satisfies the given condition string lexo_small(int n, int k) { string arr = ""; for(int i = 0; i < n; i++) arr += 'a'; // Iteration from the last position // in the array for (int i = n - 1; i >= 0; i--) { k -= i; // If k is a positive integer if (k >= 0) { // 'z' needs to be inserted if (k >= 26) { arr[i] = 'z'; k -= 26; } // Add the required character else { char c= (char)(k + 97 - 1); arr[i] = c; k -= arr[i] - 'a' + 1; } } else break; k += i; } return arr; } // Driver code int main() { int n = 5, k = 42; string arr = lexo_small(n, k); cout << arr; } // This code is contributed by Mohit Kumar |
chevron_right
filter_none
Java
// Java implementation of the approach import java.util.Arrays; public class Main { // Function to return the lexicographically // smallest string of length n that // satisfies the given condition public static char[] lexo_small(int n, int k) { char arr[] = new char[n]; Arrays.fill(arr, 'a'); // Iteration from the last position // in the array for (int i = n - 1; i >= 0; i--) { k -= i; // If k is a positive integer if (k >= 0) { // 'z' needs to be inserted if (k >= 26) { arr[i] = 'z'; k -= 26; } // Add the required character else { arr[i] = (char)(k + 97 - 1); k -= arr[i] - 'a' + 1; } } else break; k += i; } return arr; } // Driver code public static void main(String[] args) { int n = 5, k = 42; char arr[] = lexo_small(n, k); System.out.print(new String(arr)); } } |
chevron_right
filter_none
Python3
# Python implementation of the approach # Function to return the lexicographically # smallest string of length n that # satisfies the given condition def lexo_small(n, k): arr = ""; for i in range(n): arr += 'a'; # Iteration from the last position # in the array for i in range(n-1,-1,-1): k -= i; # If k is a positive integer if (k >= 0): # 'z' needs to be inserted if (k >= 26): arr = arr[:i] + 'z' + arr[i+1:]; k -= 26; # Add the required character else: c= (k + 97 - 1); arr = arr[:i] + chr(c) + arr[i+1:]; k -= ord(arr[i]) - ord('a') + 1; else: break; k += i; return arr; # Driver code if __name__ == '__main__': n = 5; k = 42; arr = lexo_small(n, k); print(arr); # This code contributed by PrinciRaj1992 |
chevron_right
filter_none
C#
// C# implementation of the approach using System; class GFG { // Function to return the lexicographically // smallest string of length n that // satisfies the given condition public static char[] lexo_small(int n, int k) { char []arr = new char[n]; int i; for(i = 0; i < n; i++) arr[i] = 'a' ; // Iteration from the last position // in the array for (i = n - 1; i >= 0; i--) { k -= i; // If k is a positive integer if (k >= 0) { // 'z' needs to be inserted if (k >= 26) { arr[i] = 'z'; k -= 26; } // Add the required character else { arr[i] = (char)(k + 97 - 1); k -= arr[i] - 'a' + 1; } } else break; k += i; } return arr; } // Driver code public static void Main() { int n = 5, k = 42; char []arr = lexo_small(n, k); Console.WriteLine(new string(arr)); } } // This code is contributed by AnkitRai01 |
chevron_right
filter_none
Output:
aaamz
Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.
Recommended Posts:
- Lexicographically smallest permutation of a string that can be reduced to length K by removing K-length prefixes from palindromic substrings of length 2K
- Lexicographically smallest and largest anagrams of a string containing another string as its substring
- Lexicographically smallest string whose hamming distance from given string is exactly K
- Lexicographically smallest string formed by appending a character from the first K characters of a given string
- Lexicographically smallest string formed by appending a character from first K characters of a string | Set 2
- Lexicographically smallest permutation of a string that contains all substrings of another string
- Lexicographically Smallest Permutation of length N such that for exactly K indices, a[i] > a[i] + 1
- Lexicographically smallest K-length substring containing maximum number of vowels
- Generate lexicographically smallest string of 0, 1 and 2 with adjacent swaps allowed
- Form lexicographically smallest string with minimum replacements having equal number of 0s, 1s and 2s
- Make the string lexicographically smallest and non palindromic by replacing exactly one character
- Make the string lexicographically smallest and non palindromic by swapping of adjacent pair of characters
- Order of indices which is lexicographically smallest and sum of elements is <= X
- K-th lexicographically smallest unique substring of a given string
- Lexicographically smallest string obtained after concatenating array
- Lexicographically smallest permutation of a string with given subsequences
- Lexicographically smallest string formed by removing at most one character
- Find the lexicographically smallest string which satisfies the given condition
- Queries to answer the X-th smallest sub-string lexicographically
- Swap all occurrences of two characters to get lexicographically smallest string
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.
