[LeetCode] 274. H-Index (JS)

1 年前

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題目

給定一個整數陣列 citations ，其中 citations[i] 是論文被引用次數，需返回該研究人員的論文 h 指數。

根據維基百科對h指數的定義：h指數被定義為 h 的最大值，使得給定的研究人員至少發表了 h 篇論文，並且每篇論文都被至少被引用 h 次。

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, their h-index is 3.

Example 2:

Input: citations = [1,3,1]
Output: 1

Constraints:

n == citations.length
1 <= n <= 5000
0 <= citations[i] <= 1000

解題思路

將論文被引用次數由大到小排序
排序完後從前至後遍歷，如果當前論文引用數大於等於已經遍歷個數則h指數加1

完整程式碼

/**
 * @param {number[]} citations
 * @return {number}
 */
var hIndex = function(citations) {
    let h = 0
    citations = citations.sort((a, b) => b - a)
    for (let i = 0; i < citations.length; i++) {
        if (citations[i] > 0 && citations[i] >= i + 1) {
            h++
        }
    }
    return h
};