【劍指Offer】37、數字在排序數組中出現的次數

function GetNumberOfK(data,k)
{
    var position1=binarySearch(data,k);
    var position2=binarySearch(data,k+1);
    return position2-position1;
}
function binarySearch(data,k){
    var left=0,right=data.length;
    while(left<right){
        var mid=Math.floor((right-left)/2)+left;
        if(data[mid]>=k) right=mid;
        else left=mid+1;
    }
    return left;
}
           

普通方法：

function GetNumberOfK(data,k)
{
    var start=data.indexOf(k);
    if(start===-1) return 0;
    var count=0;
    for(var i=start;i<data.length;i++){
            if(data[i]===k) count++;
            else{
                break;
            }
        }
    return count;
}