package tarefa05;

public class Map {

    public static class Pair {
        private Object key, value;

        public Pair(Object key, Object value) {
            this.key = key;
            this.value = value;
        }
    }

    private Pair[] pairs;
    private int nElements, newPosition;
    private boolean entered = false;

    public Map(){
        pairs = new Pair[2];
        nElements = 0;
    }


    public void put(Object key, Object value) {
        for (int i = 0; i<nElements; i++) {

            if (key == pairs[i].key) {
                pairs[i].value = value;
                entered = true;
            }

        } if (!entered){
        	newPosition = nElements;

        	if (newPosition+1 > pairs.length){
        		doubleSize(pairs);
        	}

        	pairs[newPosition]=new Pair(key, value);
    		nElements++;
        }
        entered = false;
    }

    public Object get(Object key) {

        for (int i=0; i<pairs.length; i++) {

            if (key == pairs[i].key) {
                return pairs[i].value;
            }

        }

        return null;
    }

    public void remove(Object key) {
    	Pair[] temp = new Pair[pairs.length];
    	int count = 0;

    	for (int i = 0; i < pairs.length; i++) {

    		if (pairs[i].key != key){
				temp[i] = pairs[i];
				count++;
    		}
    	}

    	if (nElements > count)
    		nElements--;

    	pairs = temp;
    }

    public Object[] keys (){
    	Object[] temp = new Object[nElements];

    	for (int i = 0; i < pairs.length; i++) {
			if (pairs[i]!=null){
				temp[i] = pairs[i].key;
			}
		}
    }

    public void doubleSize(Pair[] p) {
    	Pair[] temp = new Pair[p.length*2];

    	for (int i = 0; i < p.length; i++) {
			temp[i] = p[i];
		}

    	pairs = temp;
    }

}