Lösningar till övning 5

import java.util.ArrayList;
import java.util.Collections;

public class SortedArraySet<E extends Comparable<E>> implements Set<E> {

    ArrayList<E> list = new ArrayList<>();

    public SortedArraySet() {
    }

    // returns index of element or (-insertion_point - 1) if element is not found
    private int find(E e) {
            return Collections.binarySearch(list, e);
    }

    @Override
    public void add(E e) {
            int idx = find(e);
            if (idx < 0) {  // not already in list
                    idx = -idx - 1;  // compute insertion point
                    list.add(idx, e);
            }
    }

    @Override
    public void remove(E e) {
            int idx = find(e);
            if (idx >= 0) {  // is in list
                    list.remove(idx);
            }
    }

    @Override
    public boolean contains(E e) {
            return find(e) >= 0;
    }

    @Override
    public int size() {
            return list.size();
    }

}

@Override
public int compareTo(Entry o) {
        Character fstdig = Integer.toString(Math.abs(n)).charAt(0);
        Character fstdigo = Integer.toString(Math.abs(o.n)).charAt(0);
        int comp = fstdig.compareTo(fstdigo);
        if (comp != 0) return comp;
        Integer len = s.length();
        Integer leno = o.s.length();
        return leno.compareTo(len);
}

public boolean isDescendantOf(Person p) {
        if (mother != null) {
                if (mother == p) {
                        return true;
                } else {
                        if (mother.isDescendantOf(p)) return true;
                }
        }
        if (father != null) {
                if (father == p) {
                        return true;
                } else {
                        if (father.isDescendantOf(p)) return true;
                }
        }
        return false;
}

import java.util.ArrayList;
import java.util.Iterator;

public class ArrayMap<K, V> implements Map<K, V> {

    private class Entry {
            public K k;
            public V v;
            public Entry(K k, V v) {
                    this.k = k;
                    this.v = v;
            }
    }

    ArrayList<Entry> list = new ArrayList<>();

    // returns index of entry if key is in map, otherwise -1
    private int findKey(K key) {
            for (int i = 0; i < list.size(); i++) {
                    if (list.get(i).k.equals(key)) return i; 
            }
            return -1;
    }

    @Override
    public V get(K key) {
            int idx = findKey(key);
            if (idx >= 0) {
                    return list.get(idx).v;
            } else {
                    return null;
            }
    }

    @Override
    public void put(K key, V value) {
            int idx = findKey(key);
            if (idx >= 0) {  // key already in map
                    list.set(idx, new Entry(key, value));
            } else {  // key not in map
                    list.add(new Entry(key, value));
            }
    }

    @Override
    public void remove(K key) {
            int idx = findKey(key);
            if (idx >= 0) {
                    list.remove(idx);
            }
    }

    @Override
    public int size() {
            return list.size();
    }

    private class KeysIterator implements Iterator<K> {

            Iterator<Entry> iter;

            KeysIterator() {
                    iter = list.iterator();
            }

            @Override
            public boolean hasNext() {
                    return iter.hasNext();
            }

            @Override
            public K next() {
                    return iter.next().k;
            }

    }

    @Override
    public Iterator<K> keysIterator() {
            return new KeysIterator();
    }
}