数字在排序数组中出现的次数

import java.util.Arrays;
public class Solution {
 public int GetNumberOfK(int[] array, int k) {
        if (array.length == 0)
           return 0;
        int first = First(array, 0, array.length - 1, k);
        int last = last(array, 0, array.length - 1, k);
      System.out.println("first=" + first + " last=" + last);
      if (first != -1 && last != -1)
           return (last - first + 1);
       return 0;
    }

   // 递归
    public int First(int a[], int start, int end, int k) {
       if (start >= end)
         return -1;
       int mid = (start + end) >> 1;
      if (a[mid] > k)
           return First(a, start, mid - 1, k);
      else if (a[mid] < k)
          return First(a, mid + 1, end, k);
        else if (mid - 1 >= 0 && a[mid - 1] == k)
         return First(a, start, mid - 1, k);
      else
         return mid;
  }

//循环
    public int last(int a[], int start, int end, int k) {
        int mid = (start + end) >> 1;
      while (start <= end) {
            if (a[mid] > k)
               end = mid - 1;
           else if (a[mid] < k)
              start = mid + 1;
         else if (mid + 1 <= a.length - 1 && a[mid + 1] == k)
              start = mid + 1;
         else
             return mid;
          mid = (start + end) >> 1;
      }
        return -1;
   }
}