剑指offer 数字在排序数组中出现的次数

public int getFisrtK(int[] arr, int k, int start, int end) {
if (start > end) {
return -1;
}
int mid = (end + start) / 2;
int x = arr[mid];
if (x == k) {
if (mid > 0 && arr[mid - 1] != k || mid == 0) {
return mid;
} else {
end = mid - 1;
}
} else if (x > k) {
end = mid - 1;
} else {
start = mid + 1;
}
return getFisrtK(arr, k, start, end);
}

public int getLastK(int[] arr, int len, int k, int start, int end) {
if (start > end) {
return -1;
}
int mid = (end + start) / 2;
int x = arr[mid];
if (x == k) {
if (mid < len - 1 && arr[mid + 1] != k || mid == len - 1) {
return mid;
} else {
start = mid + 1;
}
} else if (x > k) {
end = mid - 1;
} else {
start = mid + 1;
}
return getLastK(arr, len, k, start, end);
}

public int GetNumberOfK(int[] array, int k) {
int count = 0;
if (array != null && array.length > 0) {
int first = getFisrtK(array, k, 0, array.length - 1);
int last = getLastK(array, array.length, k, 0, array.length - 1);
System.out.println(first + " " + last);
if (first > -1 && last > -1) {
count = last - first + 1;
}
}
return count;
}