Master this problem using the Digit DP pattern.
When approaching Numbers At Most N Given Digit Set, look for key problem signals that suggest using the Digit DP pattern. Focus on reducing redundant iterations, maintaining state invariant, and optimizing space-time complexity.
Key Invariant
Maintain optimal range bounds or hash frequency state during traversal.
Expected Complexity
Time: O(N) or O(N log N) | Space: O(1) to O(N)
Study Resource
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