Solution: Count and Say
Explore how to solve the count and say sequence problem by learning to track consecutive digit occurrences efficiently. Understand the algorithm that builds each sequence element by describing the previous one using run-length encoding, and see how to implement this in C# for optimized time and space performance.
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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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