UVALive 6135 Environment Protection (Simpson)

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转载请注明出处，谢谢http://blog.csdn.net/ACM_cxlove?viewmode=contents by---cxlove

非常裸的题。。。二分之后，求曲线交部分的面积。

我只是保存自适应Simpson模板的。。

#include <iostream>#include <cstdio>#include <cmath>using namespace std;const double eps = 1e-10;double w , h , area , a[4][10];int k;double function (double x , double *p , double *q , double y) {    double up = 0 , down = 0;    for (int i = 0 ; i <= k ; i ++) {        up = up * x + p[i];        down = down * x + q[i];    }    return max (y , up / down);}double simpson_formula (double l , double r , double *p , double *q , double y) {    return (function (l , p , q , y) + 4 * function ((l + r) / 2.0 , p , q , y) + function (r , p , q , y)) * (r - l) / 6.0;}double simpson (double l , double r , double *p , double *q , double y) {    double m = (l + r) / 2.0;    double ans = simpson_formula (l , r , p , q , y);    if (fabs (ans - simpson_formula (l , m , p , q , y) - simpson_formula (m , r , p , q , y)) < eps) return ans;    return simpson (l , m , p , q , y) + simpson (m , r , p , q , y);}double gao (double low , double high) {    double mid , ans = -1;    int t = 50;    while (t --) {        mid = (low + high) / 2.0;        double now = simpson (0 , w , a[0] , a[1] , mid) - simpson (0 , w , a[2] , a[3] , mid);        if (now > area) ans = mid , low = mid;        else high = mid;    }    return ans;}int main () {    #ifndef ONLINE_JUDGE        freopen ("input.txt" , "r" , stdin);        // freopen ("output.txt" , "w" , stdout);    #endif    while (scanf ("%lf %lf %lf %d" , &w , &h , &area , &k) != EOF) {        for (int i = 0 ; i < 4 ; i ++)            for (int j = k ; j >= 0 ; j --) {                scanf ("%lf" , &a[i][j]);            }        printf ("%.5f\n" , -gao (-h , 0));    }    return 0;}