Minimum Operations to Make Binary Array Elements Equal to One II Python/Java solution

Most implementations use a single loop with a flip parity variable. Python, Java, C++, and JavaScript solutions all follow the same pattern: iterate through the array, compute the effective bit using the flip state, and increment the operation count whenever the effective value is 0.

What is the best approach for Minimum Operations to Make Binary Array Elements Equal to One II?

The optimal approach is a greedy linear scan with a toggle state. Iterate from left to right and track whether previous suffix flips inverted the current values. If the effective bit becomes 0, perform a flip and toggle the state. This solves the problem in O(n) time with O(1) extra space.

Is Minimum Operations to Make Binary Array Elements Equal to One II asked at Google/Amazon/Meta?

Greedy array‑transformation problems with suffix operations appear frequently in interviews at companies like Google, Amazon, and Meta. Variants that require tracking flip parity or lazy toggling are common because they test reasoning about state changes and optimal greedy decisions.

What data structure is used in Minimum Operations to Make Binary Array Elements Equal to One II?

The problem primarily uses a simple array traversal combined with a greedy state variable. No complex data structures are required. The solution maintains a flip counter or boolean toggle to represent the effect of previous suffix operations.

What is the time complexity of Minimum Operations to Make Binary Array Elements Equal to One II?

The optimal solution runs in O(n) time because the array is scanned once from left to right. Each index performs constant work to compute the effective bit and possibly toggle the flip state. The space complexity is O(1) since only a counter or boolean state is maintained.

Description Hints 2 Solution Video 9:00

3192. Minimum Operations to Make Binary Array Elements Equal to One II

Q: Is Minimum Operations to Make Binary Array Elements Equal to One II easy or hard?

The problem is typically rated Medium difficulty. The array traversal is straightforward, but recognizing that suffix flips can be represented using a toggle state is the key insight that makes the O(n) greedy solution possible.

Q: How to solve Minimum Operations to Make Binary Array Elements Equal to One II in O(n)?

Traverse the array while maintaining a flip parity or toggle state that represents whether the suffix has been inverted by previous operations. Compute the effective value of each element considering that state. If the effective value is 0, start a flip operation at that index and toggle the state. Continue until the end of the array.

Medium65.1% acceptance1 company

You are given a binary array nums.

You can do the following operation on the array any number of times (possibly zero):

Choose any index i from the array and flip all the elements from index i to the end of the array.

Flipping an element means changing its value from 0 to 1, and from 1 to 0.

Return the minimum number of operations required to make all elements in nums equal to 1.

Example 1:

Input: nums = [0,1,1,0,1]

Output: 4

Explanation:
We can do the following operations:

Choose the index i = 1. The resulting array will be nums = [0,0,0,1,0].
Choose the index i = 0. The resulting array will be nums = [1,1,1,0,1].
Choose the index i = 4. The resulting array will be nums = [1,1,1,0,0].
Choose the index i = 3. The resulting array will be nums = [1,1,1,1,1].

Example 2:

Input: nums = [1,0,0,0]

Output: 1

Explanation:
We can do the following operation:

Choose the index i = 1. The resulting array will be nums = [1,1,1,1].

Constraints:

1 <= nums.length <= 10⁵
0 <= nums[i] <= 1

Asked at 1 company

Uber

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Hints open one at a time

Hint 1

The only way to change nums[0] to 1 is by performing an operation with index i = 0.

Hint 2

Iterate from left to right and perform an operation at each index i where nums[i] is 0, and keep track of how many operations are currently performed on the suffix.

9:00

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