街角_祝福

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数组循环左移

题:

对于有n个元素的数组 int a[n]={....};写一个高效算法将数组内容循环左移m位
比如: int a[6] ={1,2,3,4,5,6} ,循环左移3位得到结果{456123},
要求:
1不允许另外申请数组空间,但可以申请少许变量
2不允许采用每次左移


代码:

#include <stdio.h>
void ReverArrayN(int a[],int n, int k)
{
	int i;
	for( i=0; i<k/2; i++ )//三个for函数可以写成一个函数的,其实
	{
		a[i] = a[i]^a[k-1-i];
		a[k-1-i] = a[i]^a[k-1-i];;
		a[i] = a[i]^a[k-1-i];
	}
	/*for( i=0; i<n; i++ )
 	{
	 	printf("%d ",a[i]);
 	}
 	printf("\n");*/
	for( i=k; i<(k+n)/2; i++ )
	{
		a[i] = a[i]^a[n-1-(i-k)];
		a[n-1-(i-k)] = a[i]^a[n-1-(i-k)];
		a[i] = a[i]^a[n-1-(i-k)];
	}
	/*for( i=0; i<n; i++ )
 	{
	 	printf("%d ",a[i]);
 	}
 	printf("\n");*/
	for( i=0; i<n/2; i++)
	{
		a[i] = a[i]^a[n-1-i];
		a[n-1-i] = a[i]^a[n-1-i];
		a[i] = a[i]^a[n-1-i];
	}
} 
 int main(int argc, char *argv[])
 {
 	int a[] = {1,2,3,4,5,6,7,8};
 	int i;
 	ReverArrayN(a, sizeof(a)/sizeof(int), 3);
 	for( i=0; i<sizeof(a)/sizeof(int); i++ )
 	{
	 	printf("%d ",a[i]);
 	}
 	return 0;
 }



posted on 2012-10-22 08:21  街角_祝福  阅读(447)  评论(0编辑  收藏  举报