You are given a string s of lowercase English letters and an integer array shifts of the same length.
Call the shift() of a letter, the next letter in the alphabet, (wrapping around so that 'z' becomes 'a').
For example, shift('a') = 'b', shift('t') = 'u', and shift('z') = 'a'.
Now for each shifts[i] = x, we want to shift the first i + 1 letters of s, x times.
Return the final string after all such shifts to s are applied.
Example 1:
Input: s = "abc", shifts = [3,5,9]
Output: "rpl"
Explanation: We start with "abc".
After shifting the first 1 letters of s by 3, we have "dbc".
After shifting the first 2 letters of s by 5, we have "igc".
After shifting the first 3 letters of s by 9, we have "rpl", the answer.