package lab1;

import java.util.Scanner;

public class Lab1 {

    public static void main(String[] args) {
        double a = 0, b = 2, eps = 0.005;
        int n = 9;
        System.out.println("Алгоритм блочного равномерного поиска - 1");
        System.out.println("Метод касательных - 2");
        System.out.println("Выход - 3");
        int number = 0;
        Scanner sc = new Scanner(System.in);
        while (number != 3) {
            number = sc.nextInt();
            if (number == 1) {
                blockSearch(a, b, eps, n);
            } else if (number == 2) {
                tangent(a, b , eps);
            }
        }
    }

    static int tangent(double a, double b, double eps) {
        double x = 0, y = 0, y1, y2, z, z1, z2;
        int n = 0;
        y1 = function(a);
        y2 = function(b);
        z1 = derivative(a);
        z2 = derivative(b);
        boolean found = false;
        while (b - a > 2 * eps) {
            double c = ((b * z2 - a * z1) - (y2 - y1)) / (z2 - z1);
            y = function(c);
            n++;
            z = derivative(c);
            if (z == 0) {
                x = c;
                found = true;
                break;
            } else if (z < 0) {
                a = c;
                y1 = y;
                z1 = z;
            } else {
                b = c;
                y2 = y;
                z2 = z;
            }
        }
        if (!found) {
            x = (a + b) / 2;
            y = function(x);
        }
        System.out.println("X = " + x);
        System.out.println("Y = " + y);
        System.out.println("n = " + n);
        System.out.println();
        return n;
    }

    static double function(double x) {
        return Math.pow(x, 2) + 8 * Math.exp(0.55 * x);
    }

    static double derivative(double x) {
        return 2 * x + ( 22 * Math.exp(0.55 * x) ) / 5;
    }

    static int blockSearch(double a, double b, double eps, int n) {
        double x = (a + b) / 2;
        double y = function(x);
        double xi = 0, yi = 0, minxi = Double.MIN_VALUE, minyi = Double.MIN_VALUE;
        while (b - a > 2 * eps) {
            minxi = Double.MIN_VALUE;
            minyi = Double.MIN_VALUE;
            for (int i = 1; i <= n; i++) {
                xi = a + i * (b - a) / (n + 1);
                yi = function(xi);
                if (minyi == Double.MIN_VALUE || yi < minyi) {
                    minxi = xi;
                    minyi = yi;
                }
            }
            a = minxi - (b - a) / (n + 1);
            b = minxi + (b - a) / (n + 1);
        }
        System.out.println("X = " + minxi);
        System.out.println("Y = " + minyi);
        System.out.println("n = " + n);
        return n;
    }
}