Fr.java

import java.util.*;
import java.io.*;
 
class Fr
{
 
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
 
 
        while(br.ready())
        {
            String line = br.readLine();
            StringTokenizer st = new StringTokenizer(line);
            int numNodes = Integer.parseInt(st.nextToken());
            int centralNode = Integer.parseInt(st.nextToken());
            doTestCase(br, numNodes, centralNode);
 
        }
    }
 
    public static void doTestCase(BufferedReader br, int numNodes, int centralNode) throws IOException {
        HubNode[] nodes = new HubNode[numNodes];
        for (int i = 0; i < nodes.length; i++) {
            nodes[i] = new HubNode();
 
        }
 
        nodes[centralNode - 1].setCentral();
 
 
 
        for (int i = 0; i < (numNodes - 1); i++) {
            String line = br.readLine();
            StringTokenizer st = new StringTokenizer(line);
            int nodeA = Integer.parseInt(st.nextToken());
            int nodeB = Integer.parseInt(st.nextToken());
            int effort = Integer.parseInt(st.nextToken());
 
            if(nodeA == centralNode || nodeB == centralNode) { //jeden z nich je central
                if(nodeA == centralNode) {
                    nodes[nodeA - 1].addChild(nodes[nodeB - 1]);
                    nodes[nodeB - 1].setEffort(effort);
 
                }else {
                    nodes[nodeB - 1].addChild(nodes[nodeA - 1]);
                    nodes[nodeA - 1].setEffort(effort);
                }
            }else { //ani jeden
                if(!nodes[nodeA - 1].hasSetEffort()) { //na tenhle jsem jeste nenastavil effort
                    nodes[nodeA - 1].setEffort(effort);
                    nodes[nodeB - 1].addChild(nodes[nodeA - 1]);
                }else {
                    nodes[nodeB - 1].setEffort(effort);
                    nodes[nodeA - 1].addChild(nodes[nodeB - 1]);
                }
 
            }
 
        }
 
        System.out.println(nodes[centralNode - 1].getEffort());
 
        for (int i = 0; i < nodes.length; i++) {
            HubNode hubNode = nodes[i];
         //   System.out.println("node #"+(i+1)+", "+hubNode.getChildren().size()+" children, effort = "+hubNode.getEffort());
 
        }
 
 
    }
 
 
 
 
}
 
 
class HubNode {
 
    protected int effort = 0;
    protected boolean setEffort = false;
    protected boolean central = false;
    protected ArrayList<HubNode> children = new ArrayList<HubNode>();
 
    public int getEffort() {
 
        if(children.size() == 0) {// System.out.println("getChildren == 0");
            //koncovej uzel
            return effort;
        }
 
        int childEffort = 0;
        for(HubNode n : getChildren()) {
            childEffort += n.getEffort();
        }
 
        return (effort > childEffort || central) ? childEffort : effort;
 
 
    }
 
    void setCentral() {
        central = true;
    }
 
    public boolean hasSetEffort() {
        return setEffort;
    }
 
    public void setEffort(int effort) {
        setEffort = true;
        this.effort = effort;
    }
 
    public ArrayList<HubNode> getChildren() {
        return children;
    }
 
    public void addChild(HubNode child) {
       // System.out.println("Adding child ");
        children.add(child);
    }
}