Submission #3065234

---

Source Code Expand

import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.PriorityQueue;

public class Main {

  private static void solve() {
    int n = ni();
    int[] from = new int[n - 1];
    int[] to = new int[n - 1];
    int[] w = new int[n - 1];
    int[] idx = new int[n - 1];
    for (int i = 0; i < n - 1; i ++) {
      from[i] = ni() - 1;
      to[i] = ni() - 1;
      w[i] = ni();
      idx[i] = i;
    }
    
    int[][][] g = packWU(n, from, to, idx);

    Comparator<Integer> cmp = (o1, o2) -> w[o1] == w[o2] ? o1 - o2 : w[o1] - w[o2];
    List<PriorityQueue<Integer>> qlist = new ArrayList<>();;
    
    PriorityQueue<Integer> sq = new PriorityQueue<>(cmp);
    int[] edgeSet = new int[n - 1];
    for (int i = 0; i < n - 1; i ++) {
      sq.add(i);
    }
    qlist.add(sq);
    
    int[] left = new int[n];
    int[] right = new int[n];
    
    int q = ni();
    for (int i = 0; i < q; i ++) {
      int type = ni();
      if (type == 1) {
        int e = ni() - 1;
        int d = ni();
        qlist.get(edgeSet[e]).remove(e);
        w[e] = d;
        qlist.get(edgeSet[e]).add(e);
      } else {
        int e = ni() - 1;
        if (w[e] == Integer.MIN_VALUE) {
          out.println(-1);
          continue;
        }
        int v = qlist.get(edgeSet[e]).poll();
        out.println(v + 1);
        w[v] = Integer.MIN_VALUE;

        int lc = dfs(from[v], to[v], g, w, left);
        int rc = dfs(to[v], from[v], g, w, right);
        
        int[] next = lc < rc ? left : right;
        int cnt = Math.min(lc, rc);

        
        PriorityQueue<Integer> nq = new PriorityQueue<>(cmp);
        PriorityQueue<Integer> cq = qlist.get(edgeSet[v]);
        int ni = qlist.size();
        for (int j = 0; j < cnt; j ++) {
          nq.add(next[j]);
          cq.remove(next[j]);
          edgeSet[next[j]] = ni;
        }
        qlist.add(nq);
      }
    }
  }
  
  private static int dfs(int now, int pre, int[][][] g, int[] w, int[] ret) {
    ArrayDeque<int[]> q = new ArrayDeque<>();
    q.add(new int[] {now, pre});

    int ptr = 0;
    while (q.size() > 0) {
      int[] e = q.poll();
      now = e[0];
      pre = e[1];
      for (int[] f : g[now]) {
        if (f[0] == pre || w[f[1]] == Integer.MIN_VALUE) continue;
        q.add(new int[] {f[0], now});
        ret[ptr ++] = f[1];
      }
    }
    return ptr;
  }

  public static int[][][] packWU(int n, int[] from, int[] to, int[] w){ return packWU(n, from, to, w, from.length); }
  public static int[][][] packWU(int n, int[] from, int[] to, int[] w, int sup)
  {
      int[][][] g = new int[n][][];
      int[] p = new int[n];
      for(int i = 0;i < sup;i++)p[from[i]]++;
      for(int i = 0;i < sup;i++)p[to[i]]++;
      for(int i = 0;i < n;i++)g[i] = new int[p[i]][2];
      for(int i = 0;i < sup;i++){
          --p[from[i]];
          g[from[i]][p[from[i]]][0] = to[i];
          g[from[i]][p[from[i]]][1] = w[i];
          --p[to[i]];
          g[to[i]][p[to[i]]][0] = from[i];
          g[to[i]][p[to[i]]][1] = w[i];
      }
      return g;
  }
  
  public static void main(String[] args) {
    new Thread(null, new Runnable() {
      @Override
      public void run() {
        long start = System.currentTimeMillis();
        String debug = System.getProperty("debug");
        if (debug != null) {
          try {
            is = java.nio.file.Files.newInputStream(java.nio.file.Paths.get(debug));
          } catch (Exception e) {
            throw new RuntimeException(e);
          }
        }
        reader = new java.io.BufferedReader(new java.io.InputStreamReader(is), 32768);
        solve();
        out.flush();
        tr((System.currentTimeMillis() - start) + "ms");
      }
    }, "", 64000000).start();
  }

  private static java.io.InputStream is = System.in;
  private static java.io.PrintWriter out = new java.io.PrintWriter(System.out);
  private static java.util.StringTokenizer tokenizer = null;
  private static java.io.BufferedReader reader;

  public static String next() {
    while (tokenizer == null || !tokenizer.hasMoreTokens()) {
      try {
        tokenizer = new java.util.StringTokenizer(reader.readLine());
      } catch (Exception e) {
        throw new RuntimeException(e);
      }
    }
    return tokenizer.nextToken();
  }

  private static double nd() {
    return Double.parseDouble(next());
  }

  private static long nl() {
    return Long.parseLong(next());
  }

  private static int[] na(int n) {
    int[] a = new int[n];
    for (int i = 0; i < n; i++)
      a[i] = ni();
    return a;
  }

  private static char[] ns() {
    return next().toCharArray();
  }

  private static long[] nal(int n) {
    long[] a = new long[n];
    for (int i = 0; i < n; i++)
      a[i] = nl();
    return a;
  }

  private static int[][] ntable(int n, int m) {
    int[][] table = new int[n][m];
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        table[i][j] = ni();
      }
    }
    return table;
  }

  private static int[][] nlist(int n, int m) {
    int[][] table = new int[m][n];
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        table[j][i] = ni();
      }
    }
    return table;
  }

  private static int ni() {
    return Integer.parseInt(next());
  }

  private static void tr(Object... o) {
    if (is != System.in)
      System.out.println(java.util.Arrays.deepToString(o));
  }
}

Submission Info

Judge Result