Watch 10 video solutions for Shifting Letters II, a medium level problem involving Array, String, Prefix Sum. This walkthrough by NeetCodeIO has 13,456 views views. Want to try solving it yourself? Practice on FleetCode or read the detailed text solution.
You are given a string s of lowercase English letters and a 2D integer array shifts where shifts[i] = [starti, endi, directioni]. For every i, shift the characters in s from the index starti to the index endi (inclusive) forward if directioni = 1, or shift the characters backward if directioni = 0.
Shifting a character forward means replacing it with the next letter in the alphabet (wrapping around so that 'z' becomes 'a'). Similarly, shifting a character backward means replacing it with the previous letter in the alphabet (wrapping around so that 'a' becomes 'z').
Return the final string after all such shifts to s are applied.
Example 1:
Input: s = "abc", shifts = [[0,1,0],[1,2,1],[0,2,1]] Output: "ace" Explanation: Firstly, shift the characters from index 0 to index 1 backward. Now s = "zac". Secondly, shift the characters from index 1 to index 2 forward. Now s = "zbd". Finally, shift the characters from index 0 to index 2 forward. Now s = "ace".
Example 2:
Input: s = "dztz", shifts = [[0,0,0],[1,1,1]] Output: "catz" Explanation: Firstly, shift the characters from index 0 to index 0 backward. Now s = "cztz". Finally, shift the characters from index 1 to index 1 forward. Now s = "catz".
Constraints:
1 <= s.length, shifts.length <= 5 * 104shifts[i].length == 30 <= starti <= endi < s.length0 <= directioni <= 1s consists of lowercase English letters.