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Write the method
int doubles(ArrayList<Integer> list1, ArrayList<Integer> list2)
which takes two integer reading lists as parameters.
The method returns the number of elements found in both list 1 and list 2.
Example method call:
public static void main(String[] args){
ArrayList<Integer> list1 = new ArrayList<>();
ArrayList<Integer> list2 = new ArrayList<>();
list1.add(1);
list1.add(2);
list1.add(3);
list2.add(3);
list2.add(4);
list2.add(5);
list2.add(6);
int t = doubles(list1, list2);
System.out.println("Doubles: " + t);
}
Program outputs:
Doubles: 1
import java.util.Random;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.stream.Collectors;
public class Test{
public static void main(String[] args){
final Random r = new Random();
test(new int[]{1,2,3,4,5,6,7,8}, new int[]{5,6,7,8,9,10,11,12});
test(new int[]{10,20,30,40,50,60,70}, new int[]{25,30,35,40,45,50});
test(new int[]{1,9,2,8,3,7,4,6}, new int[]{10,11,12,3,14,15,16,7,4,99,1,98,2});
}
public static void test(int[] l1, int[] l2) {
ArrayList<Integer> list1 = new ArrayList<>();
for (int a : l1) {
list1.add(a);
}
ArrayList<Integer> list2 = new ArrayList<>();
for (int a : l2) {
list2.add(a);
}
System.out.println("Testing with lists ");
System.out.println("" + list1);
System.out.println("and");
System.out.println("" + list2);
System.out.println("Doubles: " + doubles(list1, list2));
System.out.println("");
}
//ADD
//ASSUME BOTH list1, list2 do not contain dupe elements
public static int doubles(ArrayList<Integer> list1, ArrayList<Integer> list2) {
int count = 0;
// // check Double dtype of each element
// for (int i = 0; i < list1.size(); i++) {
// if (list1.get(i) instanceof Double) {
// count++;
// }
// }
// for (int i = 0; i < list2.size(); i++) {
// if (list2.get(i) instanceof Double) {
// count++;
// }
// }
for (int i: list1) {
if (list2.contains(i)) {
count++;
}
}
return count;
}
}
Testing with lists
[1, 2, 3, 4, 5, 6, 7, 8]
and
[5, 6, 7, 8, 9, 10, 11, 12]
Doubles: 4
Testing with lists
[10, 20, 30, 40, 50, 60, 70]
and
[25, 30, 35, 40, 45, 50]
Doubles: 3
Testing with lists
[1, 9, 2, 8, 3, 7, 4, 6]
and
[10, 11, 12, 3, 14, 15, 16, 7, 4, 99, 1, 98, 2]
Doubles: 5
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