The logic behind this code is to find the majority elements in an input array nums
. A majority element is defined as an element that appears more than n/3
times in the array, where n
is the length of the array. The code achieves this by iterating through the sorted array and keeping track of the count of each element.
Here’s a step-by-step explanation of the logic:
1. Initial Setup:
- An empty
ArrayList
calledresult
is created to store the majority elements found. - If the length of the input array
nums
is less than 3, it’s a special case because in small arrays, any element that appears once or twice is considered a majority element. In this case, the code simply adds unique elements to theresult
list (ensuring no duplicates) and returns it.
2. Sorting:
- If the input array has 3 or more elements, it sorts the array in ascending order using
Arrays.sort(nums)
. Sorting the array simplifies the process of counting the occurrences of each element because identical elements will be adjacent to each other after sorting.
3. Counting Elements:
- The code then iterates through the sorted array using a loop.
- It maintains a
count
variable initialized to 1 to keep track of how many times the current element appears. - If the current element is the same as the next element (i.e., nums[i] == nums[i+1]), it increments the
count
because it has encountered another occurrence of the same element. - If the count is greater than 1 (meaning there is a repeated element) and the current element is not the same as the next element, it means that the current element has ended its consecutive appearances. In this case, the
count
is reset to 1.
4. Checking for Majority Elements:
- After counting the occurrences of each element in the sorted array, the code checks if the
count
of the current element is greater than or equal togt + 1
, wheregt
is calculated asnums.length / 3
. If this condition is met, it means that the current element appears more thann/3
times in the original unsorted array. - When this condition is satisfied, the current element is added to the
result
list (if it’s not already in the list to avoid duplicates), and thecount
is reset to 1.
5. Final Result:
- Once the loop has iterated through the entire sorted array, the
result
list contains the majority elements that satisfy the condition of appearing more thann/3
times in the input array.