C语言数据结构基石之时间与空间复杂度详解

// 请计算⼀下Func1中++count语句总共执⾏了多少次？
void Func1(int N)
{
	int count = 0;
	for (int i = 0; i < N; ++i)
	{
		for (int j = 0; j < N; ++j)
		{
			++count;
		}
	}
	for (int k = 0; k < 2 * N; ++k)
	{
		++count;
	}
	int M = 10;
	while (M--)
	{
		++count;
	}
}

#include<stdio.h>
#include<time>
int main()
{
	int i = 0;
	int begin = clock();
	int x = 10;
	for(i = 0; i < n; i++)
	{
		x++;
	}
	int end = clock();
	//计算运行时间
	printf("%dms", end - begin);
	return 0;
}

#include<stdio.h>
int main()
{
	int x = 0;
	scnaf("%d", &x);
	printf("%d", x);
	return 0;
}

// 计算Func2的时间复杂度？
void Func2(int N)
{
	int count = 0;
	for (int k = 0; k < 2 * N; ++k)
	{
		++count;
	}
	int M = 10;
	while (M--)
	{
		++count;
	}
	printf("%d\n", count);
}

// 计算Func3的时间复杂度？
void Func3(int N, int M)
{
	int count = 0;
	for (int k = 0; k < M; ++k)
	{
		++count;
	}
	for (int k = 0; k < N; ++
		k)
	{
		++count;
	}
	printf("%d\n", count);
}

#include<stdio.h>
int main()
{
	int x = 0;
	int begin = clock();
	int n = 100000;
	for (int i = 0; i < n; i++)
	{
		for (int j = 0; j < n; j++)
		{
			x++;
		}
	}
	int end = clock();
	printf("%d\n", x);
	printf("%dms\n", end - begin);
	return 0;
}

void func5(int n)
{
	int cnt = 1;
	while (cnt < n)
	{
		cnt *= 2;
	}
}

// 计算阶乘递归Fac的时间复杂度？

long long Fac(size_t N)
{
	if(0 == N)
	return Fac(N-1)*N;
}

// 计算BubbleSort的时间复杂度？
void BubbleSort(int* a, int n)
{
	assert(a);
	for (size_t end = n; end > 0; --end)
	{
		int exchange = 0;
		for (size_t i = 1; i < end; ++i)
		{
			if (a[i-1] > a[i])
			{
			Swap(&a[i-1], &a[i]);
			exchange = 1;
			}
		}
	if (exchange == 0)
	break;
	}
}

void reverse(int* nums, int left, int right)
{
	while (left < right)
	{
		int tap = nums[left];
		nums[left] = nums[right];
		nums[right] = tap;
		left++;
		right--;
	}
}
int main()
{
	int nums[] = { 1,2,3,4,5,6,7 };
	int numsSize = sizeof(nums) / sizeof(nums[0]);
	int k = 0;
	scanf("%d", &k);
	k %= numsSize;
	reverse(nums, 0, numsSize - k - 1);
	reverse(nums, numsSize - k, numsSize - 1);
	reverse(nums, 0, numsSize - 1);
	for (int i = 0; i < numsSize; i++)
	{
		printf("%d ", nums[i]);
	}
	return 0;
}