codeforces 404B - Marathon

題目鏈接：http://codeforces.com/problemset/problem/404/B

題目大意：運動員沿a*a的正方形跑步，教練每b米送一次水，問教練每次在哪裏等他。

題目分析：注意精度，可以先擴大10000倍，輸出的時候再除以100000，另外一些中間變量注意用long long保存。

代碼參考：

#include<map>
#include<set>
#include<cmath>
#include<queue>
#include<stack>
#include<cstdio>
#include<string>
#include<cstring>
#include<sstream>
#include<iostream>
#include<algorithm>
#include<functional>
using namespace std;
typedef long long LL;

int main()
{
	LL n, i, j, k;
	double ans, x, y;

	while (~scanf("%lf%lf%I64d", &x, &y, &n))
	{
		double m = 100000;
		LL a = x * m + 0.5;
		LL d = y * m + 0.5;
		LL sum = 0;

		for (i = 1; i <= n; ++i)
		{
			sum += d;
			sum %= (4 * a);

			if (sum <= a)
			{
				printf("%f 0.000000\n", sum / m);
			}
			else
				if (sum <= 2 * a)
				{
					printf("%f %f\n", a / m, (sum - a) / m);
				}
				else
					if (sum <= 3 * a)
					{
						printf("%f %f\n", (3 * a - sum) / m, a / m);
					}
					else
					{
						printf("0.000000 %f\n", (4 * a - sum) / m);
					}
		}
	}

	return 0;
}