UVa 11121 Base -2 / 进制转换

#include <stdio.h>
int n;
int main()
{
	int cas = 1,n,k,t,i;
	int a[100];
	scanf("%d",&t);
	while(t--)
	{
		scanf("%d",&n);
		k = 0;
		while(1)
		{
			a[k++] = n % (-2);
			n /= (-2);
			if(a[k-1] == -1)
			{
				a[k-1] = 1;
				n++;
			}
			if(n == 0)
				break;
		}
		printf("Case #%d: ",cas++);
		for(i = k - 1;i >= 0; i--)
			printf("%d",a[i]);
		puts("");
	}
	return 0;
}