Smallest String With A Given Numeric Value.py

# Runtime: 1870 ms (Top 22.43%) | Memory: 15.5 MB (Top 41.47%)
class Solution:
    def getSmallestString(self, n: int, k: int) -> str:
        ans = ['a']*n # Initialize the answer to be 'aaa'.. length n
        val = n #Value would be length as all are 'a'

        for i in range(n-1, -1, -1):
            if val == k: # if value has reached k, we have created our lexicographically smallest string
                break
            val -= 1 # reduce value by one as we are removing 'a' and replacing by a suitable character
            ans[i] = chr(96 + min(k - val, 26)) # replace with a character which is k - value or 'z'
            val += ord(ans[i]) - 96 # add the value of newly appended character to value

        return ''.join(ans) # return the ans string in the by concatenating the list