2207848_ac_15ms_32k.c

北大大牛代码 1240道题的原代码 超级权威

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

int n, no, tx, ty;
struct node
{
	int x, y;
}pt[51];

int cmp(const void *a,const void *b)
{
	struct node *aa = (struct node *)a;
	struct node *bb = (struct node *)b;

	if(aa->x==tx&&aa->y==ty)
		return -1;
	if(bb->x==tx&&bb->y==ty)
		return 1;
	if(aa->x==tx)
		if(aa->y>ty)
			return 1;
		else
			return -1;
	if(bb->x==tx)
		if(bb->y>ty)
			return -1;
		else
			return 1;
	return (aa->y-ty)*1.0/(aa->x-tx)-(bb->y-ty)*1.0/(bb->x-tx)>0?1:-1;
}

void input()
{
	int stx, sty;
	int i, j, x, y, t;

	n = 0;t = 10000;
	while(scanf("%d%d",&x,&y)==2)
	{
		if(!n)
			stx = x,sty = y;
		pt[n].x = x;pt[n].y = y;
		n++;
		if(x<t)
		{
			t = x;
			no = n-1;
		}
	}
	tx = pt[no].x;ty = pt[no].y;
	qsort(pt,n,sizeof(pt[0]),cmp);
	for(i = 0; i < n; i++)
	{
		if(pt[i].x==stx&&pt[i].y==sty)
		{
			for(j = i; j < i+n; j++)
				printf("(%d,%d)\n",pt[j%n].x,pt[j%n].y);
			break;
		}
	}
}

int main()
{
	input();
	return 1;
}