/**
 * Created by guchenghao on 16/3/5.
 */
import java.util.Scanner;

public class lagrange {

    public static int sum(int x[],int y[],int m ) {

        int s = 0;

        int j = 0;
        int h = 0;

        while (j < y.length){
            h = lan(x,m,j);
            s += y[j]*h;
            j++;
        }
        return s;
    }

    public  static int lan(int x[],int m,int j) {
        int i;
        int h = 1;

        for (i = 0; i < x.length; i++) {

            if ( i == j) {
                continue;
            } else {
                h = h * ((m - x[i]) / (x[j] - x[i]));
            }
        }

        return h;
    }


    public static void main(String[] args) {

        int[] x = new int[100];
        int[] y = new int[100];

        Scanner scan = new Scanner(System.in);
        System.out.println("请输入组数:");
        int n = scan.nextInt();
        System.out.println("请输入插值基函数中未知量:");
        int m = scan.nextInt();

        System.out.println("请给X和Y两个数组赋初值:");
        for (int i = 0; i < n; i++) {
            System.out.println("请给X赋值:");
            x[i] = scan.nextInt();
            System.out.println("请给Y赋值:");
            y[i] = scan.nextInt();
        }
        int sumup;
        sumup = sum(x,y,m);
        System.out.println("插值基函数所得的结果为:" + sumup);
    }

}