BZOJ 1011: [HNOI2008]遥远的行星

/*
BZOJ 1011: [HNOI2008]遥远的行星

给跪了。。
模糊预估算法
由精度误差的保证来计算答案
*/
#include <cstdio>
#include <iostream>
#define Max 100005
#define rg register
typedef double flo; flo m[Max], s[Max];
int main (int argc, char *argv[])
{
int N; flo A, Answer = 0; scanf ("%d%lf", &N, &A); rg int i, j, k;
for (i = 1; i <= N; ++ i)
{
j = (int) (A * i + 1e-8);
scanf ("%lf", &m[i]); Answer = 0;
if (i <= 500) for (k = 1; k <= j; ++ k) Answer += m[k] * m[i] / (i - k);
else Answer = s[j] * m[i] / (i - j / 2);
printf ("%f\n", Answer); s[i] = s[i - 1] + m[i];
}
return 0;
}