Solution: Count and Say
Explore how to solve the count and say sequence problem by efficiently tracking consecutive digits using run-length encoding. Understand how to build each term by describing the previous string, optimizing the approach to use minimal data tracking. This lesson helps you apply the knowing what to track pattern to handle frequency-based coding challenges effectively.
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Statement
The “count and say” is a sequence of strings built by describing the previous string:
The sequence starts with
countAndSay(1) = “1”For
n > 1,countAndSay(n)is created by run-length encoding the stringcountAndSay(n - 1).
Run-length encoding (RLE) works by grouping identical consecutive characters and replacing each group with the count of characters followed by the character itself. For example, the string “15224” is read as: one 1, one 5, two 2s, and one 4, producing “11152214”.
Given a positive integer n, return the
Constraints:
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