洛谷P4525 【模板】自适应辛普森法1(simpson积分)

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2.732937

// luogu-judger-enable-o2
#include<cstdio>
#include<cmath>
double a, b, c, d, L, R;
double F(double x) {
    return (c * x + d) / (a * x + b);
}
double sim(double l, double r) {
    return (F(l) + F(r) + 4 * F((l + r) / 2)) * (r - l) / 6;
}
double asr(double L, double R, double eps, double ans) {
    double mid = (L + R) / 2;
    double LL = sim(L, mid), RR = sim(mid, R);
    if(fabs(LL + RR - ans) < eps) return LL + RR;
    else return asr(L, mid, eps / 2, sim(L, mid)) + asr(mid, R, eps / 2, sim(mid, R));
}
main() {
    #ifdef WIN32
    freopen("a.in", "r", stdin);
    #endif
    scanf("%lf %lf %lf %lf %lf %lf", &a, &b, &c, &d, &L, &R);
    printf("%lf", asr(L, R, 1e-6, sim(L, R)));
}