oral_quiz->#排序数组中数字出现的次数#

#include <stdio.h>

bool g_bRightNumber = false;
void MyGetNumberHelp(int* data, int start, int end, int** first, int** last, int k);
int MyGetNumber(int* data, int length, int k) {
	g_bRightNumber = false;
	if(data == NULL || length <=0)
		return 0;

	int** first = &data;
	int* lastn = data+length-1;
	int** last = &lastn;
	MyGetNumberHelp(data, 0, length-1, first, last, k);

	int number = *last-*first+1;
	delete first;
	delete last;
	return g_bRightNumber ? number : 0;
}

void MyGetNumberHelp(int* data, int start, int end, int** first, int** last, int k) {
	if(start > end) return;

	int mid = (start+end) >> 1;
	if(data[mid] > k)
		MyGetNumberHelp(data, start, mid-1, first, last, k);
	else if(data[mid] < k)
		MyGetNumberHelp(data, mid+1, end, first, last, k);
	else {
		if(!g_bRightNumber)
			g_bRightNumber = true;
		if(mid>0 && mid<*last-data) {
			if(data[mid-1] < k) {
				*first = &data[mid];
				MyGetNumberHelp(data, start, mid-1, first, last, k);
			}
			else if(data[mid+1] > k) {
				*last = &data[mid];
				MyGetNumberHelp(data, mid+1, end, first, last, k);
			}
			else {
				MyGetNumberHelp(data, mid+1, end, first, last, k);
				MyGetNumberHelp(data, start, mid-1, first, last, k);
			}
		}
	}
}

//=========================hht's=============================
int GetFirstK(int* data, int length, int k, int start, int end) {
	if(start > end)
		return -1;

	int middleIndex = (start+end) >> 1;
	int middleData = data[middleIndex];

	if(middleData == k) {
		if((middleIndex > 0 && data[middleIndex-1] != k) || middleIndex == 0)
			return middleIndex;
		else
			end = middleIndex-1;
	}
	else if(middleData > k)
		end = middleIndex - 1;
	else
		start = middleIndex + 1;

	return GetFirstK(data, length, k, start, end);
}

int GetLastK(int* data, int length, int k, int start, int end) {
	if(start > end)
		return -1;

	int middleIndex = (start+end) >> 1;
	int middleData = data[middleIndex];

	if(middleData == k) {
		if((middleIndex < length-1 && data[middleIndex+1] != k) || middleIndex == length-1)
			return middleIndex;
		else
			start = middleIndex + 1;
	}
	else if(middleData < k)
		start = middleIndex + 1;
	else
		end = middleIndex - 1;

	return GetLastK(data, length, k, start, end);
}

int GetNumberOfK(int* data, int length, int k) {
	int number = 0;
	if(data != NULL && length >= 0) {
		int first = GetFirstK(data, length, k, 0, length-1);
		int last = GetLastK(data, length, k, 0, length-1);
		if(first > -1 && last > -1)
			number = last-first+1;
	}

	return number;
}


// ====================测试代码====================
void Test(const char* testName, int data[], int length, int k, int expected)
{
    if(testName != NULL)
        printf("%s begins: ", testName);

//    int result = MyGetNumber(data, length, k);
    int result = GetNumberOfK(data, length, k);
    if(result == expected)
        printf("Passed.\n");
    else
        printf("Failed.\n");
}

// 查找的数字出现在数组的中间
void Test1()
{
    int data[] = {1, 2, 3, 3, 3, 3, 4, 5};
    Test("Test1", data, sizeof(data) / sizeof(int), 3, 4);
}

// 查找的数组出现在数组的开头
void Test2()
{
    int data[] = {3, 3, 3, 3, 4, 5};
    Test("Test2", data, sizeof(data) / sizeof(int), 3, 4);
}

// 查找的数组出现在数组的结尾
void Test3()
{
    int data[] = {1, 2, 3, 3, 3, 3};
    Test("Test3", data, sizeof(data) / sizeof(int), 3, 4);
}

// 查找的数字不存在
void Test4()
{
    int data[] = {1, 3, 3, 3, 3, 4, 5};
    Test("Test4", data, sizeof(data) / sizeof(int), 2, 0);
}

// 查找的数字比第一个数字还小，不存在
void Test5()
{
    int data[] = {1, 3, 3, 3, 3, 4, 5};
    Test("Test5", data, sizeof(data) / sizeof(int), 0, 0);
}

// 查找的数字比最后一个数字还大，不存在
void Test6()
{
    int data[] = {1, 3, 3, 3, 3, 4, 5};
    Test("Test6", data, sizeof(data) / sizeof(int), 6, 0);
}

// 数组中的数字从头到尾都是查找的数字
void Test7()
{
    int data[] = {3, 3, 3, 3};
    Test("Test7", data, sizeof(data) / sizeof(int), 3, 4);
}

// 数组中的数字从头到尾只有一个重复的数字，不是查找的数字
void Test8()
{
    int data[] = {3, 3, 3, 3};
    Test("Test8", data, sizeof(data) / sizeof(int), 4, 0);
}

// 数组中只有一个数字，是查找的数字
void Test9()
{
    int data[] = {3};
    Test("Test9", data, sizeof(data) / sizeof(int), 3, 1);
}

// 数组中只有一个数字，不是查找的数字
void Test10()
{
    int data[] = {3};
    Test("Test10", data, sizeof(data) / sizeof(int), 4, 0);
}

// 鲁棒性测试，数组空指针
void Test11()
{
    Test("Test11", NULL, 0, 0, 0);
}

int main(int argc, char* argv[])
{
    Test1();
    Test2();
    Test3();
    Test4();
    Test5();
    Test6();
    Test7();
    Test8();
    Test9();
    Test10();
    Test11();

    return 0;
}