274.go

package p274

import "sort"

/**
Given an array of citations (each citation is a non-negative integer) of a researcher, write a function to compute the researcher's h-index.

According to the definition of h-index on Wikipedia: "A scientist has index h if h of his/her N papers have at least h citations each, and the other N − h papers have no more than h citations each."

For example, given citations = [3, 0, 6, 1, 5], which means the researcher has 5 papers in total and each of them had received 3, 0, 6, 1, 5 citations respectively. Since the researcher has 3 papers with at least 3 citations each and the remaining two with no more than 3 citations each, his h-index is 3.

Note: If there are several possible values for h, the maximum one is taken as the h-index.


H指数的计算基于其研究者的论文数量及其论文被引用的次数。赫希认为：一个人在其所有学术文章中有N篇论文分别被引用了至少N次，他的H指数就是N。
如美国耶鲁大学免疫学家理查德·弗来沃发表的900篇文章中，有107篇被引用了107次以上，他的H指数是107。
*/

func hIndex(citations []int) int {
	sort.Ints(citations)
	h := 1
	for i := len(citations) - 1; i >= 0; i-- {
		if citations[i] < h {
			break
		}
		h++
	}
	return h - 1
}