Medium Difficulty
H Index



Counting Sort



Link to algo

To find the researcher's h-index from an array of citations, you can follow the steps below in JavaScript:

  1. Sort the array of citations in non-decreasing order.
  2. Initialize a variable hIndex to 0, which will store the maximum h-index.
  3. Iterate through the sorted array of citations, starting from the largest value.
    • For each iteration, check if the current citation value is greater than or equal to the current hIndex + 1.
      • If true, increment hIndex by 1.
      • If false, break the loop.
  4. After the loop, hIndex will contain the maximum h-index for the given array.

Here's the JavaScript code that implements the above steps:

function calculateHIndex(citations) {
  citations.sort((a, b) => b - a); // Sort the array in non-decreasing order
  let hIndex = 0;
  for (let i = 0; i < citations.length; i++) {
    if (citations[i] >= hIndex + 1) {
    } else {
  return hIndex;
// Example usage:
const citations = [3, 0, 6, 1, 5];
const hIndex = calculateHIndex(citations);
console.log("The researcher's h-index is: " + hIndex);

The time complexity of this solution is O(n log n), where n is the number of elements in the citations array. This is due to the initial sorting of the array. The subsequent loop to calculate the h-index has a linear time complexity of O(n), as it iterates through the sorted array once.