Solution: Count and Say
Explore how to implement the count and say sequence by tracking consecutive digits and applying run-length encoding. Understand the iterative approach that builds each term based on the previous one, improving efficiency with a single-pass solution. This lesson helps you master the core tracking technique essential for handling similar coding patterns.
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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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