LeetCode 3671 - Sum of Beautiful Subsequences

Let a subsequence of nums be any sequence multiples. citeturn0search1turn0search2 check whether it is strictly increasing, compute its GCD, and add that GCD to the answer. This is correct because every valid subsequence is examined exactly once.

leetcodehardarraymathbinary-indexed-treenumber-theory

LeetCode Problem 3671

Difficulty: 🔴 Hard
Topics: Array, Math, Binary Indexed Tree, Number Theory

Solution

Problem Understanding

Let a subsequence of nums be any sequence multiples. citeturn0search1turn0search2 check whether it is strictly increasing, compute its GCD, and add that GCD to the answer.

This is correct because every valid subsequence is examined exactly once.

Unfortunately, there are 2^n subsequences. Even for `n = um queries efficiently. citeturn0search1turn0 Force | O(2^n · n) | O(n) | Enumerates all dynamic programming recurrence for counting strictly increasing subsequences. Thus every valid increasing subsequence is counted exactly once, establishing correctness. citeturnself, n: int): self.n = n self.bit = [0] * ( assigned to exactly one GCD, namely its true GCD.