274. H-Index

common sense 直接sort 然后找citations > len-i

可以直接用一个bucket记录 然后大于N的全部记录在N上 因为hindex不可能大于N

https://leetcode.com/problems/h-index/discuss/70768/Java-bucket-sort-O(n)-solution-with-detail-explanation

 

class Solution {
    public int hIndex(int[] citations) {
        if(citations.length == 0) return 0;
        Arrays.sort(citations);
        int lo = 0, hi = citations.length - 1;
        int len = citations.length;
        for(int i = 0; i < len; i++){
            if(citations[i] >= len - i){
                return len - i;
            }
        }
        return 0;
        
    }
}