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public int (int[] array , int k) {
int count = 0;
if (array != null || array.length <1) {
int firstIdx = getFirstK(array, k, 0, array.length - 1);
int lastIdx = getLastK(array, k, 0, array.length - 1);
if (firstIdx != -1 && lastIdx != -1)
count = lastIdx - firstIdx + 1;
}
return count;
}
private int getFirstK(int[] array, int k, int start, int end) {
if (start > end)
return -1;
int middle = (start + end) / 2;
if (array[middle] < k)
return getFirstK(array, k, middle + 1, end);
else if (array[middle] > k)
return getFirstK(array, k, start, middle - 1);
else {
if (middle == 0 || (middle > 0 && array[middle - 1] != k))
return middle;
else
return getFirstK(array, k, start, middle - 1);
}
}
private int getLastK(int[] array, int k, int start, int end) {
if (start > end)
return -1;
int middle = (start + end) / 2;
if (array[middle] < k)
return getLastK(array, k, middle + 1, end);
else if (array[middle] > k)
return getLastK(array, k, start, middle - 1);
else {
if (middle == array.length - 1 || (middle < array.length - 1 && array[middle + 1] != k))
return middle;
else
return getLastK(array, k, middle + 1, end);
}
}
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