MST - Minimum Spanning Tree

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import static java.lang.Integer.parseInt;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.PriorityQueue;
import java.util.StringTokenizer;

public class Main {

    static BufferedReader reader;
    static StringTokenizer tok;
    static int n, m;
    static long cost;
    static ArrayList<pair> graph[];
    static PriorityQueue<pair> q;
    static boolean visited[];

    public static void main(String[] args) throws IOException {

        Input();
        sol();
    }

    public static void Input() throws IOException {
        reader = new BufferedReader(new InputStreamReader(System.in));
        tok = new StringTokenizer(reader.readLine());
        n = parseInt(tok.nextToken());
        m = parseInt(tok.nextToken());
        graph = new ArrayList[n + 1];
        for (int i = 1; i <= n; i++) {
            graph[i] = new ArrayList<pair>();
        }
        for (int i = 1; i <= m; i++) {
            tok = new StringTokenizer(reader.readLine());
            int x = parseInt(tok.nextToken()), y = parseInt(tok.nextToken()), w = parseInt(tok.nextToken());
            graph[x].add(new pair(y, w));
            graph[y].add(new pair(x, w));
        }

    }

    public static void sol() {

        visited = new boolean[n + 1];
        q = new PriorityQueue<pair>(Comparator.comparing((pair obj) -> obj.weight));
        q.add(new pair(1, 0));
        visited[1] = true;

        while (!q.isEmpty()) {

            pair obj = q.poll();
            if (!visited[obj.node]) {
                visited[obj.node] = true;
                cost+=obj.weight;
            }
            for (pair x : graph[obj.node]) {
                if (!visited[x.node]) {
                    q.add(x);
                }
            }

        }
        System.out.println(cost);
    }

    static class pair {

        int node, weight;

        public pair(int node, int weight) {
            this.node = node;
            this.weight = weight;
        }

    }

}