0274. H Index

# 274. H-Index#

## 题目 #

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.”

Example 1:

``````
Input: citations = [3,0,6,1,5]
Output: 3
Explanation: [3,0,6,1,5] 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, her h-index is 3.

``````

Note:

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

## 代码 #

``````
package leetcode

// 解法一
func hIndex(citations []int) int {
n := len(citations)
buckets := make([]int, n+1)
for _, c := range citations {
if c >= n {
buckets[n]++
} else {
buckets[c]++
}
}
count := 0
for i := n; i >= 0; i-- {
count += buckets[i]
if count >= i {
return i
}
}
return 0
}

// 解法二
func hIndex1(citations []int) int {
quickSort164(citations, 0, len(citations)-1)
hIndex := 0
for i := len(citations) - 1; i >= 0; i-- {
if citations[i] >= len(citations)-i {
hIndex++
} else {
break
}
}
return hIndex
}

``````