275. H-Index II

[Tcdian]

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。

h 指数的定义: “h 代表“高引用次数”（high citations），一名科研人员的 h 指数是指他（她）的 （N 篇论文中）总共有 h 篇论文分别被引用了至少 h 次。（其余的 N - h 篇论文每篇被引用次数不多于 h 次。）"

Example

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

Note

• 如果 h 有多有种可能的值 ，h 指数是其中最大的那个。

[Tcdian]

Solution

• JavaScript Solution

/**
 * @param {number[]} citations
 * @return {number}
 */
var hIndex = function(citations) {
    let left = 0;
    let right = citations.length - 1;
    while(left <= right) {
        const mid = (left + right) >> 1;
        if (citations[mid] < citations.length - mid) {
            left = mid + 1;
        } else {
            right = mid - 1;
        }
    }
    return citations.length - left;
};

• TypeScript Solution

function hIndex(citations: number[]): number {
    let left = 0;
    let right = citations.length - 1;
    while(left <= right) {
        const mid = (left + right) >> 1;
        if (citations[mid] < citations.length - mid) {
            left = mid + 1;
        } else {
            right = mid - 1;
        }
    }
    return citations.length - left;
};