Maximum Number of Operations With the Same Score I

Difficulty: Easy | Acceptance: 52.90% | Paid: No Topics: Array, Simulation

Given an array nums consisting of positive integers.

Return the maximum number of operations you can perform on the array.

In each operation:

• Select two elements from nums. If their sum equals a target value, remove them from the array and continue.
• The target value is the sum of the first two elements removed in the first operation.

You must remove the first two elements and calculate their sum as the target. Then, continue removing pairs of elements from the beginning of the array whose sum equals this target.

• Table of Contents
• Examples
• Constraints
• Simulation with While Loop
• Simulation with For Loop

Examples

Example 1:
Input: nums = [3,2,1,4,5]
Output: 2
Explanation: 
- First operation: Remove nums[0] and nums[1]. The sum is 3 + 2 = 5. target = 5.
- Second operation: Remove nums[0] and nums[1]. The sum is 1 + 4 = 5. target = 5.
- No more operations can be performed.

Example 2:
Input: nums = [3,2,6,1,4]
Output: 1
Explanation:
- First operation: Remove nums[0] and nums[1]. The sum is 3 + 2 = 5. target = 5.
- Second operation: Remove nums[0] and nums[1]. The sum is 6 + 1 = 7 ≠ target.
- No more operations can be performed.

Example 3:
Input: nums = [1,1,1,1,1,1]
Output: 3
Explanation:
- First operation: Remove nums[0] and nums[1]. The sum is 1 + 1 = 2. target = 2.
- Second operation: Remove nums[0] and nums[1]. The sum is 1 + 1 = 2. target = 2.
- Third operation: Remove nums[0] and nums[1]. The sum is 1 + 1 = 2. target = 2.
- No more elements remain.

Constraints

2 <= nums.length <= 100
1 <= nums[i] <= 1000

Simulation with While Loop

Intuition We simulate the process by iterating through the array in pairs, checking if each pair’s sum matches the initial target sum.

Steps

• Calculate the target as the sum of the first two elements
• Use a while loop to process pairs from the beginning
• For each pair, check if their sum equals the target
• If yes, increment count and move to the next pair
• If no, break the loop

from typing import List

class Solution:
    def maxOperations(self, nums: List[int]) -> int:
        if len(nums) < 2:
            return 0
        
        target = nums[0] + nums[1]
        count = 0
        i = 0
        
        while i + 1 < len(nums):
            if nums[i] + nums[i + 1] == target:
                count += 1
                i += 2
            else:
                break
        
        return count

Complexity

• Time: O(n) where n is the length of the array
• Space: O(1) constant extra space
• Notes: Simple and efficient approach with early termination

Simulation with For Loop

Intuition Same logic as the while loop approach, but using a for loop with step size of 2 to iterate through pairs.

Steps

• Calculate the target as the sum of the first two elements
• Use a for loop with step 2 to process pairs
• For each pair, check if their sum equals the target
• If yes, increment count; if no, break the loop

from typing import List

class Solution:
    def maxOperations(self, nums: List[int]) -> int:
        if len(nums) < 2:
            return 0
        
        target = nums[0] + nums[1]
        count = 0
        
        for i in range(0, len(nums) - 1, 2):
            if nums[i] + nums[i + 1] == target:
                count += 1
            else:
                break
        
        return count

Complexity

• Time: O(n) where n is the length of the array
• Space: O(1) constant extra space
• Notes: More concise loop structure with same efficiency