学步园

/*
	实现整型数组的循环右移
	cycleMoveR1：临时空间比较大，但是时间复杂度为O(1)
	cycleMoveR2：临时空间比较小，时间复杂度为O(n)
*/

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

// 数组循环右移moveLen个
int cycleMoveR1(int arr[], int len, int moveLen)	
{
	assert(len > 0 && moveLen > 0);
	moveLen = moveLen % len;

	int *p = malloc(moveLen * sizeof(int));
	if(NULL == p)
		return 0;

	memcpy(p, arr+len-moveLen, moveLen * sizeof(int));	// 保存将被右移出数组的元素
	memmove(arr+moveLen, arr, (len - moveLen) * sizeof(int));	// 将数组最前的元素右移moveLen个
	memmove(arr, p, moveLen * sizeof(int));
	free(p);

	return 1;
}

// 数组循环右移moveLen个
int cycleMoveR2(int arr[], int len, int moveLen)	
{
	assert(len > 0 && moveLen > 0);
	moveLen = moveLen % len;

	int i, j, t, p0, p1 = 0;
	for(i = 0; i < moveLen - p1; i++)	// 循环moveLen-p1次
	{
		j = len - i - 1;
		p0 = j;							// p0保存此轮最先空出来的元素的下标
		t = arr[j];
		while(1)
		{
			if(j - moveLen >= 0)
			{
				arr[j] = arr[j - moveLen];
				j -= moveLen;
			}
			else
			{
				if(j - moveLen + len != p0)
				{
					arr[j] = arr[j - moveLen + len];
					j = j - moveLen + len;
					p1++;
				}
				else
				{
					arr[j] = t;
					break;
				}				
			}
		}		
	}

	return 1;
}


void display(int arr[], int len)
{
	int i = 0;
	for(; i < len; i++)
		printf("%d ", arr[i]);
	printf("\n");
}

int main(int argc, char *argv[])
{
	int arr[] = {1, 2, 3, 4, 5, 6};
	int len = sizeof(arr)/sizeof(int);
	int moveLen = 0;
	do 
	{
		printf("请输入循环右移的个数：");
		scanf("%d", &moveLen);
		if(moveLen <= 0)
			break;
		cycleMoveR2(arr, len, moveLen);
		display(arr, len);
	} while (1);

	return 0;
}