Available question text
Generate the k-th positive integer whose decimal representation consists only of digits 4 and 7 (the "lucky" numbers), ordered by value. The challenge is to handle large k efficiently by recognizing the bijection between binary patterns (or lengths and combinations) and lucky-number strings rather than brute-force enumeration.
Related questions
Continue with questions that share topics or the same question type.
Sources · 1 reference
These records explain where the question appears. A company tag or candidate report does not guarantee a future interview question.
Hello Interview · 1 record
No company association
Leetcode 2802. Find The K-th Lucky Number
Interview date not specified · 0 source reports
Source snapshot: Nov 12, 2026
View source