[LeetCode] H-Index
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.
类似于计数排序，略。
C++：
// Runtime: 4 ms
class Solution {
public:
int hIndex(vector int citations) {
int len = citations.size();
vector int cnt(len + 1, 0);
for_each(citations.begin(), citations.end(),
[len, cnt](int n){ n = len ? cnt[len]++ : cnt[n]++; });
for (int i = len; i = 0; i--)
cnt[i] = i == len ? cnt[i] : cnt[i] + cnt[i + 1];
if (cnt[i] = i)
return i;
return 0;
};
Java:
// Runtime: 1 ms
public class Solution {
public int hIndex(int[] citations) {
int len = citations.length;
int cnt[] = new int[len + 1];
for (int c : citations) {
if (c = len) {
cnt[len]++;
else {
cnt[c]++;
for (int i = len; i = 0; i--) {
cnt[i] += i == len ? 0 : cnt[i + 1];
if (cnt[i] = i) {
return i;
return 0;
}
LeetCode 275. H-Index II 给定一位研究者论文被引用次数的数组（被引用次数是非负整数），数组已经按照升序排列。编写一个方法，计算出研究者的 h 指数。
Follow up for H-Index: What if the citations array is sorted in ascending order? Could you optimize your algorithm? Hint:
[LeetCode] H-Index II This problem is designed specifically to use binary search. In fact, in H-Index, someone has already used this idea (you may refer to this post :-)) The code is as follows.
[LeetCode] H-Index If you ve read the Wikipedia article of H-Index, there is already a neat formula there for computing the h-index, which is written below using the notations of the problem.