How do you solve Minimum Moves to Balance Circular Array on LeetCode?

Minimum Moves to Balance Circular Array (LeetCode #3776) can be solved using Brute Force or Optimal Solution. The optimal approach is Optimal Solution with O(n) time complexity and O(1) space complexity. Key insight: Only one negative balance simplifies the problem.

What is the time complexity of Minimum Moves to Balance Circular Array?

The optimal solution for Minimum Moves to Balance Circular Array runs in O(n) time and uses O(1) space. Single pass through the array leads to linear time complexity.

What is the brute force solution for Minimum Moves to Balance Circular Array?

The brute force approach for Minimum Moves to Balance Circular Array is Brute Force, with O(n²) time complexity and O(1) space complexity. This approach tries every possible transfer between neighbors to balance the array. It calculates the total moves needed for each configuration, which is inefficient. The optimal Optimal Solution approach improves this to O(n).

What algorithm or data structure is used to solve Minimum Moves to Balance Circular Array?

Minimum Moves to Balance Circular Array uses the following concepts: Array, Greedy, Sorting. The recommended patterns to study are: Greedy, Array.

What are the interview tips for Minimum Moves to Balance Circular Array?

Clarify constraints before solving. Discuss edge cases like all positives or a single negative. Explain your thought process clearly.

What are common mistakes when solving Minimum Moves to Balance Circular Array?

Forgetting to check total balance before processing. Assuming multiple negatives can exist.

#3776

Minimum Moves to Balance Circular Array

Medium

ArrayGreedySortingGreedyArray

LeetCode ↗

Approaches

Brute ForceOptimal

Complexity Comparison

	Brute Force	Optimal Solution★
Time	O(n²)	O(n)
Space	O(1)	O(1)

💡

Intuition

Time O(n)Space O(1)

This approach leverages the fact that only one index can be negative, allowing us to balance efficiently by transferring from positive balances in a single pass.

⚙️

Algorithm

3 steps

1Step 1: Calculate the total balance; if it's negative, return -1.
2Step 2: Identify the index with the negative balance.
3Step 3: Traverse the array, transferring from positive balances to the negative index, counting moves.

solution.py9 lines

1def minMoves(balance):
2    total = sum(balance)
3    if total < 0: return -1
4    moves = 0
5    neg_index = balance.index(next(b for b in balance if b < 0))
6    for i in range(len(balance)):
7        if i != neg_index:
8            moves += max(0, balance[i])
9    return moves + -balance[neg_index]

ℹ

Complexity note: Single pass through the array leads to linear time complexity.

1Only one negative balance simplifies the problem.
2Total balance must be non-negative for a solution.

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