Decode Ways — Medium Coding Interview Question

A message containing letters A-Z can be encoded as '1' to '26'. Given a string s of digits, return the number of ways to decode it.

Example

Input: s = "12"

Output: 2

Explanation: 'AB' or 'L'.

Constraints

• 1 ≤ s.length ≤ 100
• s contains only digits and may have leading zeros

Topics & Companies

Topics: dp

Asked by: Amazon, Google, Meta, Microsoft, Bloomberg

Optimal Solution Complexity

Time complexity: O(n). Space complexity: O(1).

Practice more

• All DSA Problems
• DSA Patterns