878654. Find H-Index
Here is the detailed blog post for the problem:
Find H-Index
Summary
The problem requires you to find the H-Index, which is a measure of the productivity and citation impact of the publication of a scholar. The H-Index is defined as the largest number of papers that have at least that many citations each. For example, if a researcher has published 5 papers with at least 3 citations each, then their H-Index is 3. This problem involves sorting and manipulating arrays.
Detailed Explanation
The given array represents the citation count for different publications. To find the H-Index, we need to sort this array in descending order and then iterate over it until we find the first element that has a citation count less than its index plus one. The size of this array will be our H-Index.
Here is a step-by-step breakdown of the solution:
- Sort the given array in descending order.
- Initialize the H-Index to 0.
- Iterate over the sorted array from left to right.
- For each element, check if its citation count is less than or equal to its index plus one.
- If it is, then update the H-Index with the current index and break out of the loop.
- Return the updated H-Index.
The time complexity for this algorithm is O(n log n) due to the sorting step, where n is the number of publications (or elements in the array). The space complexity is O(1), as we only need a constant amount of space to store the H-Index and iterate variables.
Optimized Solutions
Here are the optimized solutions for this problem in different languages:
Java
import java.util.Arrays;
public class Main {
public static int hIndex(int[] citations) {
Arrays.sort(citations);
int n = citations.length;
for (int i = 0; i < n; i++) {
if (citations[i] < i + 1) {
return i;
}
}
return n;
}
}