Lesson 1.3

SimpleIntersection.java

import java.util.*;

public class SimpleIntersection {

    private BinarySearch search = new BinarySearch();

    public List<Integer> intersection(int[] a, int[] b) {
        List<Integer> result = new LinkedList<>();
        for (int x : a) {
            for (int y : b) {
                if (x == y) result.add(x);
            }
        }
        return result;
    }

    public List<Integer> intersectionFast(int[] a, int[] b) {
        // Write your code here
        
        return null;
    }

    public void mergeSort(int[] input) {
        Arrays.sort(input);
    }

    public static void main(String[] args) {
        SimpleIntersection inter = new SimpleIntersection();
        System.out.println(inter.intersection(new int[]{4, 7, 5, 2, 3}, new int[]{4, 2, 3, 9, 1}));
        System.out.println(inter.intersection(new int[]{4, 6, 11, 2, 3}, new int[]{5, 11, 3, 9, 1}));

        // Write your code here

    }
}

BinarySearch.java

public class BinarySearch {
    public boolean binarySearch(int x, int[] sortedNumbers) {
        int end = sortedNumbers.length - 1;
        int start = 0;
        while (start <= end) {
            int mid = (end - start) / 2 + start;
            if (sortedNumbers[mid] == x) return true;
            else if (sortedNumbers[mid] > x) end = mid - 1;
            else start = mid + 1;
        }
        return false;
    }

    public static void main(String args[]) {
        BinarySearch binarySearch = new BinarySearch();
        System.out.println(binarySearch.binarySearch(7, new int[]{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}));
        System.out.println(binarySearch.binarySearch(0, new int[]{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}));
    }
}