题解 | #数字在升序数组中出现的次数#

/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 *
 * 
 * @param data int整型一维数组 
 * @param k int整型 
 * @return int整型
 */
function GetNumberOfK(data, k) {
    // write code here
    if(!data.length) return 0
    let left = 0;
    let right = data.length;
    //二分左右界
    while (left < right) {
        let mid = Math.floor((left + right) / 2);
        if (data[mid] >= k) {
            right = mid;
        } else {
            left = mid + 1;
        }
    }
    let start = left;
    left = 0;
    right = data.length;
    while (left < right) {
        let mid = Math.floor((left + right) / 2);
        if (data[mid] <= k) {
            left = mid + 1;
        } else {
            right = mid;
        }
    }
    let end = right;
    return end - start;
}
module.exports = {
    GetNumberOfK: GetNumberOfK
};