What is the time complexity of LeetCode 2422. Merge Operations to Turn Array Into a Palindrome?

The Python solution on this page runs in O(n), where n is the length of the array.

What is the space complexity of LeetCode 2422. Merge Operations to Turn Array Into a Palindrome?

The Python solution on this page uses O(1) auxiliary space.

Merge Operations to Turn Array Into a Palindrome — LeetCode 2422 Python Solution

MediumLeetCode PremiumGreedyArrayTwo Pointers

Problem: #2422
Pattern: Two Pointers
Reading time: 3 min
Source: leetcode.com

The problem

You are given an array nums consisting of positive integers. You can perform the following operation on the array any number of times: Choose any two adjacent elements and replace them with their sum.

Example

Input: nums = [4,3,2,1,2,3,1]
Output: 2
Explanation: We can turn the array into a palindrome in 2 operations as follows:

Python solution

Python

class Solution:
    def minimumOperations(self, nums: List[int]) -> int:
        i, j = 0, len(nums) - 1
        a, b = nums[i], nums[j]
        ans = 0
        while i < j:
            if a < b:
                i += 1
                a += nums[i]
                ans += 1
            elif b < a:
                j -= 1
                b += nums[j]
                ans += 1
            else:
                i, j = i + 1, j - 1
                a, b = nums[i], nums[j]
        return ans

Complexity

Measure	Complexity
Time	O(n), where n is the length of the array
Space	O(1) auxiliary

Pattern: Two Pointers

Use the order already in the input to discard half the search space at every step. LeetCode 2422. Merge Operations to Turn Array Into a Palindrome is filed here because LeetCode tags it Two Pointers, which is the vocabulary this hub collects.

The two pointers guide has the Python template for the pattern and the 201 LeetCode problems that use it.

Frequently asked questions

How hard is LeetCode 2422. Merge Operations to Turn Array Into a Palindrome?: LeetCode 2422. Merge Operations to Turn Array Into a Palindrome is rated Medium on LeetCode.
What is the time complexity of LeetCode 2422. Merge Operations to Turn Array Into a Palindrome?: The Python solution on this page runs in O(n), where n is the length of the array.
What is the space complexity of LeetCode 2422. Merge Operations to Turn Array Into a Palindrome?: The Python solution on this page uses O(1) auxiliary space.
What topics does LeetCode 2422. Merge Operations to Turn Array Into a Palindrome cover?: LeetCode 2422. Merge Operations to Turn Array Into a Palindrome is tagged Greedy, Array and Two Pointers on LeetCode.
Is LeetCode 2422. Merge Operations to Turn Array Into a Palindrome a premium problem?: Yes. LeetCode 2422. Merge Operations to Turn Array Into a Palindrome is a LeetCode Premium problem, so the full statement and test cases require a paid LeetCode subscription.