how can i verify the third condition
package com.codegym.task.task07.task0717;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
public class Solution {
public static void main(String[] args) throws Exception {
ArrayList<String> list = new ArrayList<String>();
ArrayList<String> Nlist = new ArrayList<String>();
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
for(int i = 0; i < 10; i++){
String s = reader.readLine();
list.add(s);
}
ArrayList<String> result = doubleValues(list);
for(String v: result){
System.out.println(v);
}
}
public static ArrayList<String> doubleValues(ArrayList<String> list) {
for(int i = 0; i < 20; i+=2){
list.add(i+1, list.get(i));
// list.add(3, list.get(i));
// System.out.println(i);
}
return null;
}
}