#3669

Balanced K-Factor Decomposition

Medium
MathBacktrackingNumber TheoryBacktrackingDynamic Programming
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Approaches

Brute ForceOptimal
Complexity Comparison
Brute ForceOptimal Solution
Time
O(n²)
O(n)
Space
O(1)
O(n)
💡

Intuition

Time O(n)Space O(n)

Distribute the factors of n as evenly as possible among k integers to minimize the maximum difference.

⚙️

Algorithm

3 steps
  1. 1Step 1: Find all divisors of n and sort them.
  2. 2Step 2: Use a recursive function to select k divisors such that their product equals n.
  3. 3Step 3: Ensure the selected divisors are as close in value as possible.
solution.py14 lines
1def balanced_k_factor(n, k):
2    def dfs(start, picked, prod, path):
3        if len(path) == k:
4            if prod == n:
5                return path
6            return None
7        for i in range(start, len(divs)):
8            if prod * divs[i] > n:
9                break
10            res = dfs(i, picked + 1, prod * divs[i], path + [divs[i]])
11            if res:
12                return res
13    divs = sorted([i for i in range(1, n + 1) if n % i == 0])
14    return dfs(0, 0, 1, [])

Complexity note: Finding divisors is linear, and the recursive search is efficient due to pruning.

  • 1Distributing factors evenly minimizes differences.
  • 2Recursive backtracking can efficiently explore combinations.

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