Simple conv

import java.sql.SQLOutput;
import java.util.ArrayList;

public class Main {

    public static void main(String[] args) {
        int n=5;
        int m=4;
        int numS=0;
        int numM=0;
        int [] x1=new int[n];
        //ArrayList<Integer> x1 = new ArrayList<>(5);
        for (int i=0;i<n;i++)
            x1[i] = i;

        int [] x2=new int[m];
        for (int i=0;i<m;i++)
            x2[i]=i;
        int[] y=new int[n+m-1];
        int i=0;
        for (i=0;i<m;i++) {
            int z = 0;
            for (int a = 0; a < i+1; a++) {
                z += x1[a] * x2[i-a];
                numM++;
                if (a!=0)
                numS++;
            }
            y[i] = z;
        }

        int j=1;
        for (j=1;j<n-m+1;j++){
            int z = 0;
            int b = m-1;
            for (int a = j; a < m+j; a++) {
                z += x1[a] * x2[b];
                numM++;
                if (a!=j)
                    numS++;
                b--;
            }
            y[i+j-1]=z;
        }

        i=i+j-1;
        for (j=n-m+1;j<n;j++){
            int z = 0;
            int b = m-1;
            for (int a = j; a < n; a++) {
                z += x1[a] * x2[b];
                numM++;
                if (a!=j)
                    numS++;
                b--;
            }
            y[i]=z;
            i++;
        }

        System.out.print("1 sequence: ");
        for (i=0;i<n;i++){
            System.out.print(x1[i]+" ");
        }
        System.out.print("\n2 sequence: ");
        for (i=0;i<m;i++){
            System.out.print(x2[i]+" ");
        }
        System.out.print("\n amount of sums: "+numS);
        System.out.print("\n amount of mult: "+numM+"\n");
    }
}