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Codeforces Round #368 Div2 D. Persistent Bookcase

競技プログラミング Codeforces

問題

Problem - D - Codeforces

N 行 M 列のビットがあり、最初は全て 0 である。以下の 4 種類のクエリが来るので、各クエリの操作後のビットの合計を出力せよ。

  1. i 行 j 列のビットが0であれば1にする。1ならば何もしない。
  2. i 行 j 列のビットが1であれば0にする。0ならば何もしない。
  3. i 行 のビットを全て反転させる。
  4. k 回目のクエリの直後の状態へ戻す。

解法

各操作の順番はツリーとして表現することができる。各操作は十分軽いのでDFSしていけば良い。

コード

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.NoSuchElementException;

/*
                   _ooOoo_
                  o8888888o
                  88" . "88
                  (| -_- |)
                  O\  =  /O
               ____/`---'\____
             .'  \\|     |//  `.
            /  \\|||  :  |||//  \
           /  _||||| -:- |||||-  \
           |   | \\\  -  /// |   |
           | \_|  ''\---/''  |   |
           \  .-\__  `-`  ___/-. /
         ___`. .'  /--.--\  `. . __
      ."" '<  `.___\_<|>_/___.'  >'"".
     | | :  `- \`.;`\ _ /`;.`/ - ` : | |
     \  \ `-.   \_ __\ /__ _/   .-` /  /
======`-.____`-.___\_____/___.-`____.-'======
                   `=---='
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
            pass System Test!
*/

public class D {
  private static class Task {
    ArrayList<Integer>[] graph;
    int[][] queries;
    boolean[][] shelf;
    boolean[] inverted;
    int[] ans;
    int[] books;

    int N, M;

    void dfs(int v) {
      for (int u : graph[v]) {
        int type = queries[u][0];

        if (type == 1) {
          int i = queries[u][1];
          int j = queries[u][2];
          if (!inverted[i]) {
            if (shelf[i][j]) {
              ans[u] = ans[v];
              dfs(u);
            } else {
              shelf[i][j] = true;
              ans[u] = ans[v] + 1;
              books[i]++;
              dfs(u);
              shelf[i][j] = false;
              books[i]--;
            }
          } else {
            if (!shelf[i][j]) {
              ans[u] = ans[v];
              dfs(u);
            } else {
              shelf[i][j] = false;
              ans[u] = ans[v] + 1;
              books[i]++;
              dfs(u);
              shelf[i][j] = true;
              books[i]--;
            }
          }
        }

        if (type == 2) {
          int i = queries[u][1];
          int j = queries[u][2];
          if (!inverted[i]) {
            if (!shelf[i][j]) {
              ans[u] = ans[v];
              dfs(u);
            } else {
              shelf[i][j] = false;
              ans[u] = ans[v] - 1;
              books[i]--;
              dfs(u);
              shelf[i][j] = true;
              books[i]++;
            }
          } else {
            if (shelf[i][j]) {
              ans[u] = ans[v];
              dfs(u);
            } else {
              shelf[i][j] = true;
              ans[u] = ans[v] - 1;
              books[i]--;
              dfs(u);
              shelf[i][j] = false;
              books[i]++;
            }
          }
        }

        if (type == 3) {
          int i = queries[u][1];
          ans[u] = ans[v] - books[i];
          books[i] = M - books[i];
          ans[u] += books[i];
          inverted[i] = !inverted[i];
          dfs(u);
          inverted[i] = !inverted[i];
          books[i] = M - books[i];
        }

        if (type == 4) dfs(u);
      }
    }

    void solve(FastScanner in, PrintWriter out) {
      N = in.nextInt();
      M = in.nextInt();
      int Q = in.nextInt();

      queries = new int[Q + 1][];
      for (int i = 1; i <= Q; i++) {
        int type = in.nextInt();
        if (type <= 2) {
          queries[i] = new int[]{type, in.nextInt() - 1, in.nextInt() - 1};
        } else if (type == 3) {
          queries[i] = new int[]{type, in.nextInt() - 1};
        } else {
          queries[i] = new int[]{type, in.nextInt()};
        }
      }

      graph = new ArrayList[Q + 1];
      for (int i = 0; i < Q + 1; i++) {
        graph[i] = new ArrayList<>();
      }
      int cur = 0;
      int[] after = new int[Q + 1];
      for (int i = 1; i <= Q; i++) {
        int type = queries[i][0];
        if (type != 4) {
          graph[cur].add(i);
          cur = i;
        } else {
          int k = queries[i][1];
          cur = after[k];
        }
        after[i] = cur;
      }

      shelf = new boolean[N][M];
      inverted = new boolean[N];
      ans = new int[Q + 1];
      books = new int[N];
      dfs(0);

      for (int i = 1; i <= Q; i++) {
        if (queries[i][0] == 4) {
          int k = queries[i][1];
          ans[i] = ans[k];
        }
      }

      for (int i = 1; i <= Q; i++) {
        out.println(ans[i]);
      }
    }
  }

  /**
   * ここから下はテンプレートです。
   */
  public static void main(String[] args) {
    OutputStream outputStream = System.out;
    FastScanner in = new FastScanner();
    PrintWriter out = new PrintWriter(outputStream);
    Task solver = new Task();
    solver.solve(in, out);
    out.close();
  }
  private static class FastScanner {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int bufferLength = 0;

    private boolean hasNextByte() {
      if (ptr < bufferLength) {
        return true;
      } else {
        ptr = 0;
        try {
          bufferLength = in.read(buffer);
        } catch (IOException e) {
          e.printStackTrace();
        }
        if (bufferLength <= 0) {
          return false;
        }
      }
      return true;
    }

    private int readByte() {
      if (hasNextByte()) return buffer[ptr++];
      else return -1;
    }

    private static boolean isPrintableChar(int c) {
      return 33 <= c && c <= 126;
    }

    private void skipUnprintable() {
      while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
    }

    boolean hasNext() {
      skipUnprintable();
      return hasNextByte();
    }

    public String next() {
      if (!hasNext()) throw new NoSuchElementException();
      StringBuilder sb = new StringBuilder();
      int b = readByte();
      while (isPrintableChar(b)) {
        sb.appendCodePoint(b);
        b = readByte();
      }
      return sb.toString();
    }

    long nextLong() {
      if (!hasNext()) throw new NoSuchElementException();
      long n = 0;
      boolean minus = false;
      int b = readByte();
      if (b == '-') {
        minus = true;
        b = readByte();
      }
      if (b < '0' || '9' < b) {
        throw new NumberFormatException();
      }
      while (true) {
        if ('0' <= b && b <= '9') {
          n *= 10;
          n += b - '0';
        } else if (b == -1 || !isPrintableChar(b)) {
          return minus ? -n : n;
        } else {
          throw new NumberFormatException();
        }
        b = readByte();
      }
    }

    double nextDouble() {
      return Double.parseDouble(next());
    }

    double[] nextDoubleArray(int n) {
      double[] array = new double[n];
      for (int i = 0; i < n; i++) {
        array[i] = nextDouble();
      }
      return array;
    }

    double[][] nextDoubleMap(int n, int m) {
      double[][] map = new double[n][];
      for (int i = 0; i < n; i++) {
        map[i] = nextDoubleArray(m);
      }
      return map;
    }

    public int nextInt() {
      return (int) nextLong();
    }

    public int[] nextIntArray(int n) {
      int[] array = new int[n];
      for (int i = 0; i < n; i++) array[i] = nextInt();
      return array;
    }

    public long[] nextLongArray(int n) {
      long[] array = new long[n];
      for (int i = 0; i < n; i++) array[i] = nextLong();
      return array;
    }

    public String[] nextStringArray(int n) {
      String[] array = new String[n];
      for (int i = 0; i < n; i++) array[i] = next();
      return array;
    }

    public char[][] nextCharMap(int n) {
      char[][] array = new char[n][];
      for (int i = 0; i < n; i++) array[i] = next().toCharArray();
      return array;
    }
  }
}