2023.09.27 Today's Challenge

https://leetcode.com/problems/decoded-string-at-index/

LeetCode - The World's Leading Online Programming Learning Platform

역시나 스택을 이용하는 문제!

class Solution:
    def decodeAtIndex(self, s: str, k: int) -> str:
        size = 0

        for i in range(len(s)):
            if s[i].isdigit():
                size *= int(s[i])
                continue
            size += 1
        
        for i in range(len(s)-1, -1, -1):
            k = k % size

            if k == 0 and s[i].isalpha():
                return s[i]
            
            if s[i].isdigit():
                size //= int(s[i])
                continue
            size -= 1
        
        return ""