Day11- H-Index

public class Solution {
    public int hIndex(int[] citations) {
        // sorting the citations in ascending order
        Arrays.sort(citations);
        // finding h-index by linear search
        int i = 0;
        while (i < citations.length && citations[citations.length - 1 - i] > i) {
            i++;
        }
        return i; // after the while loop, i = i' + 1
    }
}

public class Solution {
    public int hIndex(int[] citations) {
        int n = citations.length;
        int[] papers = new int[n + 1];
        // counting papers for each citation number
        for (int c: citations)
            papers[Math.min(n, c)]++;
        // finding the h-index
        int k = n;
        for (int s = papers[n]; k > s; s += papers[k])
            k--;
        return k;
    }
}