H-Index II

arraybinary search

Problem Statement

Given an array of integers citations where citations[i] is the number of citations a researcher received for their i ^th paper and citations is sorted in non-descending order , return the researcher's h-index .

According to the definition of h-index on Wikipedia : The h-index is defined as the maximum value of h such that the given researcher has published at least h papers that have each been cited at least h times.

You must write an algorithm that runs in logarithmic time.

Examples

Example 1

Input: citations = [0,1,3,5,6]
Output: 3
[0,1,3,5,6] means the researcher has 5 papers in total and each of them had received 0, 1, 3, 5, 6 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, their h-index is 3.

Example 2

Input: citations = [1,2,100]
Output: 2

Constraints

n == citations.length

1 <= n <= 10 ^5

0 <= citations[i] <= 1000

citations is sorted in ascending order .

🤔

Medium

Difficulty

Topic Info

ModuleDSA

CategoryArray

Sub-topicBinary Search