[英]what is the average time complexity of using Set/TreeSet in java?
Does the below implementation using Set interface/TreeSet class in java satisfy the O(N*log(N)) average time complexity in Big-O notation. 使用Java中的Set interface / TreeSet类的以下实现是否满足Big-O表示法中的O(N * log(N))平均时间复杂度。
I am trying to find the k-th largest element in a supplied integer list with the above mentioned average time complexity. 我试图在提供的整数列表中找到具有上述平均时间复杂度的第k个最大元素。
public class JavaBuiltInSort {
public static void removeDupInIntArray(int[] ints, int k) {
Set<Integer> setString = new TreeSet<Integer>(Collections.reverseOrder());
for (int i = 0; i < ints.length; i++) {
setString.add(ints[i]);
}
System.out.println(setString);
Integer[] array = setString.toArray(new Integer[0]);
System.out.println("The kth largest element in the list is "+ array[k-1]);
}
public static void main(String[] args) {
int[] arr = { 8, 9, 4, 5, 2, 1, 6, 5, 7, 9, 5, 4, 8, 6, 3, 1, 2, 5, 4, 7, 8 };
int k = 5;
JavaBuiltInSort.removeDupInIntArray(arr,k);
}
}
This implementation provides guaranteed log(n) time cost for the basic operations (
add
,remove
andcontains
). 此实现为基本操作(add
,remove
和contains
)提供了有保证的log(n)时间成本。
You are performing a ~log(n) operation n times, hence the complexity is indeed O(n log(n)). 您正在执行~log(n)操作n次,因此复杂度确实为O(n log(n))。
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