面试题38：数字在排序数组中出现的次数

public class Solution {    public int GetNumberOfK(int [] array , int k) {        int length = array.length;        if(length == 0){            return 0;        }        int firstK = getFirstK(array, k, 0, length-1);        int lastK = getLastK(array, k, 0, length-1);        if(firstK != -1 && lastK != -1){             return lastK - firstK + 1;        }        return 0;    }    //递归写法    private int getFirstK(int [] array , int k, int start, int end){        if(start > end){            return -1;        }        int mid = (start + end) >> 1;        if(array[mid] > k){            return getFirstK(array, k, start, mid-1);        }else if (array[mid] < k){            return getFirstK(array, k, mid+1, end);        }else if(mid-1 >=0 && array[mid-1] == k){            return getFirstK(array, k, start, mid-1);        }else{            return mid;        }    }    //循环写法    private int getLastK(int [] array , int k, int start, int end){        int length = array.length;        int mid = (start + end) >> 1;        while(start <= end){            if(array[mid] > k){                end = mid-1;            }else if(array[mid] < k){                start = mid+1;            }else if(mid+1 < length && array[mid+1] == k){                start = mid+1;            }else{                return mid;            }            mid = (start + end) >> 1;        }        return -1;    }}