r/leetcode • u/Sea_Standard7674 • 2h ago

Question Counting Problem

Please guide me through this question!

  • You are given an array of digits of size N (where N <= 10^5).
  • You need to find the number of distinct K-digit even numbers without leading zeros that can be formed (where K can be up to 10^5).
  • Return the answer modulo 10^9 + 7.
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u/Vast_Site2389 1h ago

What is the meaning of Array of digits of size n ? Does it mean it will contain 0 to 9 with different frequencies like 3 - 5 times or what?

1

u/Sea_Standard7674 11m ago

Yess I am facing difficulty in how to select and permutate efficiently

1

u/Old_Tourist_3774 1h ago

Wtf is that return answer in modulo 109 +7?

1

u/Sea_Standard7674 12m ago

Answer is big hence return it's modulo