Растојание во дрво - [дрво]

Растојание во дрво Problem 4 (0 / 0)

Дадено е пополнето дрво во кое секоја врска има тежина 2. За секој пар јазли потребно е да се најде најкраткото растојание меѓу нив. Доколку не постои решение испечатете "Error".

Име на класата (Java): NodeDistance.


import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
import java.util.NoSuchElementException;

class BNode<E> {

    public E info;
    public BNode<E> left;
    public BNode<E> right;

    static int LEFT = 1;
    static int RIGHT = 2;

    public BNode(E info) {
        this.info = info;
        left = null;
        right = null;
    }

    public BNode() {
        this.info = null;
        left = null;
        right = null;
    }

    public BNode(E info, BNode<E> left, BNode<E> right) {
        this.info = info;
        this.left = left;
        this.right = right;
    }

    @Override
    public String toString() {
        return ""+info;
    }
}

class BTree<E> {

    public BNode<E> root;

    public BTree() {
        root = null;
    }

    public BTree(E info) {
        root = new BNode<E>(info);
    }

    public void makeRoot(E elem) {
        root = new BNode(elem);
    }

    public void makeRootNode(BNode<E> node) {
        root = node;
    }

    public BNode<E> addChild(BNode<E> node, int where, E elem) {

        BNode<E> tmp = new BNode<E>(elem);

        if (where == BNode.LEFT) {
            if (node.left != null)  // veke postoi element
                return null;
            node.left = tmp;
        } else {
            if (node.right != null) // veke postoi element
                return null;
            node.right = tmp;
        }

        return tmp;
    }

    public BNode<E> addChildNode(BNode<E> node, int where, BNode<E> tmp) {

        if (where == BNode.LEFT) {
            if (node.left != null)  // veke postoi element
                return null;
            node.left = tmp;
        } else {
            if (node.right != null) // veke postoi element
                return null;
            node.right = tmp;
        }

        return tmp;
    }

    private BNode<E> findNode(E x, BNode<E> root){
        if(root == null)
            return null;
        if(root.info.equals(x))
            return root;
        else {
            BNode<E> left = findNode(x,root.left);
            if(left != null)
                return left;
            else
                return findNode(x,root.right);
        }
    }

    public BNode<E> find(E x){
        return findNode(x,root);
    }

    public BNode<E> LCA(BNode<E> root, BNode<E> first, BNode<E> second){
        if(root == null)
            return null;
        if(root == first || root == second)
            return root;

        BNode<E> left = LCA(root.left, first,second);
        BNode<E> right = LCA(root.right, first,second);
        if(left != null && right != null)
            return root;
            if(left != null)
                return left;
            else
                return right;
    }

    public int distance(BNode<E> lca, BNode<E> node){
        if(lca == null)
            return 1000000;
        if(lca == node)
            return 0;
        else
            return Math.min((distance(lca.right,node)+1), (distance(lca.left,node)+1));
    }
}



interface Stack<E> {

    // Elementi na stekot se objekti od proizvolen tip.

    // Metodi za pristap:

    public boolean isEmpty ();
        // Vrakja true ako i samo ako stekot e prazen.

    public E peek ();
        // Go vrakja elementot na vrvot od stekot.

    // Metodi za transformacija:

    public void clear ();
        // Go prazni stekot.

    public void push (E x);
        // Go dodava x na vrvot na stekot.

    public E pop ();
        // Go otstranuva i vrakja elementot shto e na vrvot na stekot.
}

class ArrayStack<E> implements Stack<E> {
    private E[] elems;
    private int depth;

    @SuppressWarnings("unchecked")
    public ArrayStack (int maxDepth) {
        // Konstrukcija na nov, prazen stek.
        elems = (E[]) new Object[maxDepth];
        depth = 0;
    }


    public boolean isEmpty () {
        // Vrakja true ako i samo ako stekot e prazen.
        return (depth == 0);
    }


    public E peek () {
        // Go vrakja elementot na vrvot od stekot.
        if (depth == 0)
            throw new NoSuchElementException();
        return elems[depth-1];
    }


    public void clear () {
        // Go prazni stekot.
        for (int i = 0; i < depth; i++)  elems[i] = null;
        depth = 0;
    }


    public void push (E x) {
        // Go dodava x na vrvot na stekot.
        elems[depth++] = x;
    }


    public E pop () {
        // Go otstranuva i vrakja elementot shto e na vrvot na stekot.
        if (depth == 0)
            throw new NoSuchElementException();
        E topmost = elems[--depth];
        elems[depth] = null;
        return topmost;
    }
}



public class NodeDistance {

    public static void main(String[] args) throws Exception {
        int i, j, k;
        int index;
        String action;

        String line;

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st;

        int N = Integer.parseInt(br.readLine());

        BNode<String> nodes[] = new BNode[N];
        BTree<String> tree = new BTree<String>();

        for (i=0;i<N;i++)
            nodes[i] = new BNode<String>();

        for (i = 0; i < N; i++) {
            line = br.readLine();
            st = new StringTokenizer(line);
            index = Integer.parseInt(st.nextToken());
            nodes[index].info = st.nextToken();
            action = st.nextToken();
            if (action.equals("LEFT")) {
                tree.addChildNode(nodes[Integer.parseInt(st.nextToken())], BNode.LEFT, nodes[index]);
            } else if (action.equals("RIGHT")) {
                tree.addChildNode(nodes[Integer.parseInt(st.nextToken())], BNode.RIGHT, nodes[index]);
            } else {
                // this node is the root
                tree.makeRootNode(nodes[index]);
            }
        }


        int cases = Integer.parseInt(br.readLine());
        for (int l = 0; l < cases; l++) {
            String split[] = br.readLine().split(" +");
            String from = split[0];
            String to = split[1];

            // Vasiot kod ovde
            BNode<String> f = tree.find(from);
            BNode<String> t = tree.find(to);

            if(f == null || t == null){
                System.out.println("ERROR");
                continue;
            }

            BNode<String> lca = tree.LCA(tree.root, f,t);

            System.out.println((tree.distance(lca,f) + tree.distance(lca,t))*2);


        }
        br.close();


    }

}


8
0 A ROOT
1 B LEFT 0
2 C LEFT 1
3 D RIGHT 1
4 E RIGHT 0
5 F RIGHT 4
6 G LEFT 5
7 H RIGHT 5
3
A D
E E
G Z

Sample output

4
0
ERROR