Decode an Encoded String

Given an encoded string s with the rule: The encoding format is k[encoded_string], meaning encoded_string is repeated exactly k times. k is a positive integer. encoded_string may itself contain further encoded patterns (nesting is allowed). Decode s and return the decoded string. Requirements Correctly handle nested encodings. s contains only digits, letters, and square brackets [ and ]. Examples Input: s = "3[a]2[bc]" Output: "aaabcbc" Input: s = "3[a2[c]]" Output: "accaccacc" Constraints (typical interview setting) 1 <= len(s) <= 1e4 Decoded output length <= 1e5 Test cases Example Input 3[a]2[bc] Output aaabcbc