> 这题怎么节省时间，我按照经典的叉积方法实现，却用了500多ms,请问15ms的是怎么搞的？
#include<iostream>
using namespace std;
char in[1000010];
struct point
{
	int x,y;
}pre,now;
int cx[]={0,-1,-1,-1,0,0,0,1,1,1};
int cy[]={0,-1,0,1,-1,0,1,-1,0,1};
int main()
{
	int test,i;
	__int64 re;
	scanf("%d",&test);
	while(test--)
	{
		scanf("%s",in);
		i=0;
		pre.x=0;pre.y=0;
		now.x=0;now.y=0;
		re=0;
		while(in[i]!='5')
		{
			if(i>0 && in[i]!=in[i-1])
			{
				re+=pre.x*now.y-pre.y*now.x;
				pre=now;
				now.x=now.x+cx[in[i]-'0'];
				now.y=now.y+cy[in[i]-'0'];
			}
			else
			{
				now.x=now.x+cx[in[i]-'0'];
				now.y=now.y+cy[in[i]-'0'];
			}
			i++;
		}
		pre.x=0;pre.y=0;
		re+=pre.x*now.y-pre.y*now.x;
		if(re<0) re=-re;
		if(re%2) printf("%I64d.5\n",re/2);
		else printf("%I64d\n",re/2);
	}
	return 0;
}

• 伟哥神牛 (862) Acaini 2009-10-06 13:00:44
• 79MS...一次读入比单个来得快 (862) Acaini 2009-10-06 13:08:13