【题解】HDU7046（数学推导）

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;

int t, k;
int x_root, y_root, xl, yl, xr, yr;

inline double qpow(double base, int n)
{

    double ans = 1;
    while (n)
    {
        if (n & 1)
        {
            ans = ans * base;
        }
        base = base * base;
        n >>= 1;
    }
    return ans;
}

int main()
{
    scanf("%d", &t);
    while (t--)
    {
        scanf("%d", &k);
        scanf("%d%d%d%d%d%d", &x_root, &y_root, &xl, &yl, &xr, &yr);

        int dy = y_root - yr;
        double d = xr - xl;
        double h = (k - 1) * dy;

        double w = 0.0;

        double ans = 4 * (k - 2) + 3 * qpow(0.5, k - 2) - 2;

        ans *= 0.5 * d * dy;

        printf("%.3lf\n", ans);
    }
}