fr.cpp

// 
// File:   fr.cc
// Author: cteam030
//
// Created on October 19, 2013, 12:07 PM
//
 
#include <stdlib.h>
#include <iostream>
#include <string>
#include <vector>
 
using namespace std;
 
//
// 
//
 
struct Node {
    //int id;
    int child;
    int effort;
};
 
int getEffort(vector<Node> nodes[], int id, int effort);
 
vector<bool> banned_ids;
 
int main(int argc, char** argv) {
 
    size_t n, cent;
 
    while(cin >> n >> cent) {
        //Node nodes[n+1];
        vector<Node> nodes[n+1];
        for(size_t i = 1;i<n;i++) {
            int id,id2,eff;
            cin >> id >> id2 >> eff;
            Node n1, n2;
            n1.child = id2;
            n2.child = id;
            n1.effort = eff;
            n2.effort = eff;
 
            nodes[id].push_back(n1);
            nodes[id2].push_back(n2);
            banned_ids.push_back(false);
        }
        banned_ids.push_back(false);
        banned_ids.push_back(false);
 
 
 
        /////////////////////////
        int res = 0;
        /*for(size_t i=0; i<nodes[cent].subNodes.size(); i++) {
            res += getEffort(nodes, nodes[cent].subNodes[i]);
        }*/
 
        for(size_t i=0; i<nodes[cent].size(); i++) {
            banned_ids[cent] = true;
            res += getEffort(nodes, nodes[cent][i].child, nodes[cent][i].effort);
        }
 
        cout << res << "\n";
    }
 
    return (0);
}
 
int getEffort(vector<Node> nodes[], int id, int effort) {
    banned_ids[id] = true;
    if(nodes[id].size() <= 1){
        return nodes[id][0].effort;
    }
    int res = 0;
    for(size_t i=0; i<nodes[id].size(); i++) {
        if(!banned_ids[nodes[id][i].child])
            res += getEffort(nodes, nodes[id][i].child, nodes[id][i].effort);
    }
    if(res > effort)
        return effort;
    else
        return res;
}