Package g0801_0900.s0880_decoded_string_at_index

Class Solution

java.lang.Object
g0801_0900.s0880_decoded_string_at_index.Solution
public class Solution extends java.lang.Object
880 - Decoded String at Index.

Medium

You are given an encoded string s. To decode the string to a tape, the encoded string is read one character at a time and the following steps are taken:

  • If the character read is a letter, that letter is written onto the tape.
  • If the character read is a digit d, the entire current tape is repeatedly written d - 1 more times in total.

Given an integer k, return the kth letter ( 1-indexed) in the decoded string.

Example 1:

Input: s = “leet2code3”, k = 10

Output: “o”

Explanation: The decoded string is “leetleetcodeleetleetcodeleetleetcode”. The 10th letter in the string is “o”.

Example 2:

Input: s = “ha22”, k = 5

Output: “h”

Explanation: The decoded string is “hahahaha”. The 5th letter is “h”.

Example 3:

Input: s = “a2345678999999999999999”, k = 1

Output: “a”

Explanation: The decoded string is “a” repeated 8301530446056247680 times. The 1st letter is “a”.

Constraints:

  • 2 <= s.length <= 100
  • s consists of lowercase English letters and digits 2 through 9.
  • s starts with a letter.
  • 1 <= k <= 109
  • It is guaranteed that k is less than or equal to the length of the decoded string.
  • The decoded string is guaranteed to have less than 263 letters.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    java.lang.String
    decodeAtIndex(java.lang.String s, int k)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • decodeAtIndex

      public java.lang.String decodeAtIndex(java.lang.String s, int k)