#3266

Final Array State After K Multiplication Operations II

Hard
ArrayHeap (Priority Queue)SimulationHeapArray
LeetCode ↗

Approaches

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

Intuition

Time O(n + k log n)Space O(n)

The optimal solution leverages a priority queue (min-heap) to efficiently manage the minimum values in the array. This allows us to perform the k operations in logarithmic time, significantly reducing the overall complexity.

⚙️

Algorithm

3 steps
  1. 1Step 1: Initialize a min-heap with the elements of nums.
  2. 2Step 2: For k operations, extract the minimum element from the heap, multiply it by the multiplier, and push it back into the heap.
  3. 3Step 3: After k operations, extract all elements from the heap and apply modulo 10^9 + 7.
solution.py9 lines
1import heapq
2
3def finalArrayState(nums, k, multiplier):
4    MOD = 10**9 + 7
5    heapq.heapify(nums)
6    for _ in range(k):
7        min_val = heapq.heappop(nums)
8        heapq.heappush(nums, min_val * multiplier)
9    return [num % MOD for num in nums]

Complexity note: The time complexity is O(n + k log n) because we first build the heap in O(n) time, and each of the k operations takes O(log n) time for insertion and extraction.

  • 1Using a heap allows for efficient minimum retrieval and updates.
  • 2Understanding the impact of large k values on performance is crucial.

Solutions and explanations are original Tejav content. Problem titles © LeetCode — use the LeetCode button above for the full problem statement.