Maximizing Element Frequency with Limited Operations
In data analysis and resource allocation, it's often useful to identify the most common items or to consolidate disparate values within a certain budget. This problem challenges you to find the highest possible frequency of an element in an array after performing a limited number of increment operations, simulating a scenario where you can "tune" values but have finite resources.
Problem Description
You are given an integer array nums and an integer k. Your goal is to determine the maximum possible frequency of any element in the array after performing at most k increment operations. An increment operation consists of choosing an index i and incrementing nums[i] by 1.
Specifically, you need to:
- Identify an element
Xthat can appear with the highest frequency. - Achieve this by incrementing other elements in the array to become
X. - The total number of increments across all operations must not exceed
k. - Since you can only increment, any elements chosen to become
Xmust initially be less than or equal toX. The elementXitself must be one of the elements in the final array. It's implicitly optimal to chooseXto be the largest element in the chosen sub-array of elements you're trying to make equal.
Examples
Example 1:
Input: nums = [1, 2, 4], k = 5
Output: 3
Explanation: We want to make all elements equal to some value using at most 5 operations.
Consider sorting nums: [1, 2, 4].
If we target the largest element, 4:
- To change 1 to 4 requires 3 increments (4 - 1).
- To change 2 to 4 requires 2 increments (4 - 2).
Total increments needed: 3 + 2 = 5.
Since 5 <= k, we can make all three elements equal to 4. The array becomes [4, 4, 4].
The frequency of 4 is 3. This is the maximum possible.
Example 2:
Input: nums = [1, 4, 8, 13], k = 5
Output: 2
Explanation:
Consider sorting nums: [1, 4, 8, 13].
- If we try to make elements equal to 4:
- Change 1 to 4: 3 increments. Total cost: 3. (Frequency 2: [4, 4, 8, 13])
- Cost 3 <= k. So, frequency 2 is possible.
- If we try to make elements equal to 8:
- Change 4 to 8: 4 increments.
- Change 1 to 8: 7 increments.
- To make two elements equal to 8 (e.g., [1, 8, 8, 13]): Cost for 4->8 is 4. Total cost 4 <= k. Frequency 2 possible.
- To make three elements equal to 8 (e.g., [8, 8, 8, 13]): Cost for 1->8 is 7, cost for 4->8 is 4. Total cost 7 + 4 = 11. Cost 11 > k. Not possible.
- If we try to make elements equal to 13:
- Change 8 to 13: 5 increments.
- To make two elements equal to 13 (e.g., [1, 4, 13, 13]): Cost for 8->13 is 5. Total cost 5 <= k. Frequency 2 possible.
The maximum frequency we can achieve is 2.
Example 3:
Input: nums = [3, 9, 6], k = 2
Output: 1
Explanation:
Consider sorting nums: [3, 6, 9].
- If we try to make elements equal to 6:
- Change 3 to 6: 3 increments. Total cost: 3. Cost 3 > k. Cannot make [6, 6, 9].
- If we try to make elements equal to 9:
- Change 6 to 9: 3 increments. Total cost: 3. Cost 3 > k. Cannot make [3, 9, 9].
With k=2, we cannot make any two distinct elements equal. The maximum frequency remains 1 (each element is unique).
Constraints
1 <= nums.length <= 10^51 <= nums[i] <= 10^90 <= k <= 10^9- The answer is guaranteed to fit in a 32-bit integer.
Notes
- Since you can only increment elements, consider what this implies about the target value you would aim for. It's always optimal to make elements equal to one of the largest values in the selected group.
- Sorting the
numsarray can significantly simplify the problem structure and help in identifying potential candidates for the most frequent element. - Think about how to efficiently calculate the total cost for a contiguous subsegment of the sorted array to make all elements equal to the largest element in that subsegment. A sliding window approach could be very effective.
- The total cost for a window
[nums[i], ..., nums[j]]to make all elements equal tonums[j]is(nums[j] * (j - i + 1)) - sum(nums[i]...nums[j]). Efficiently calculating this sum for a sliding window will be crucial.