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This approach constructs the smallest lexicographical string by starting with 'a' for all characters initially. Then, it tries to modify the string starting from the end towards the beginning so that the sum of all character values becomes equal to k. We iterate backwards and replace 'a's with whatever character provides exactly the needed additional sum up to 25 (since 26 - 1 = 25, where 1 is the value of 'a').
Time Complexity: O(n), as we iterate over the string once.
Space Complexity: O(n), for the storage of the result string.
1def getSmallestString(n, k):
2 result = ['a'] * n
3 k -= n # Reducethe k by the sum of 'a's
4 index = n - 1
5 while k > 0:
6 add = min(k, 25)
7 result[index] = chr(ord('a') + add)
8 k -= add
9 index -= 1
10 return ''.join(result)
11
12# Example Usage
13print(getSmallestString(3, 27))Using Python, one can leverage lists to handle mutable string representations before joining them into a single output string. After initializing a list with 'a' characters, we iterate backwards, adjusting each character to elevate the total numeric value without disturbing the growing lexicographical sequence.
This approach generates the solution by starting with the smallest lexicographical letter 'a' and incrementally modifying the last possible position where it can introduce a remainder of the sum. We start assigning 'a' to fill the leftovers systematically from the beginning and increment positions forward when no more space is left towards the end.
Time Complexity: O(n)
Space Complexity: O(n) for storing the resulting string.
Character arrays provide a powerful method to manipulate data within Java. The Java method iterates from the back to meet the calculated sum without reorganizing or modifying dict entries.