字符串左旋

1.暴力拆解法

#include <stdio.h>
#include <assert.h>
#include <string.h>

void left_move(char* arr, int k)
{
	assert(arr != NULL);
	int i = 0;
	int len = strlen(arr);
	for (i = 0; i < k; i++)
	{
		char tmp = *arr;
		int j = 0;
		for (j = 0; j < len - 1; j++)
		{
			*(arr + j) = *(arr + j + 1);
		}
		*(arr + len - 1) = tmp;
	}

}


int main()
{
	char arr[] = "abcdef";
	left_move(arr,2);

	printf("%s\n", arr);
	return 0;
}

2.三步翻转法

void reverse(char* left, char* right)
{
	assert(left != NULL);
	assert(right != NULL);
	while(left<right)
	{
		char tmp = *left;
		*left = *right;
		*right = tmp;
		left++;
		right--;
	}

}

void left_move(char* arr, int k)
{
	assert(arr);
	int len = strlen(arr);
	assert(k < len);
	reverse(arr, arr + k - 1);
	reverse(arr + k, arr+len-1);
	reverse(arr, arr + len-1);

}
int main()
{
	char arr[] = "abcdef";
	left_move(arr,2);

	printf("%s\n", arr);
	return 0;
}