Submission #656292

#	Time	Username	Problem	Language	Result	Execution time	Memory
656292		600Mihnea	Cop and Robber (BOI14_coprobber)	C++17	60 / 100	3069 ms	5576 KiB

coprobber

#include "coprobber.h"
#include <bits/stdc++.h>

using namespace std;


const int N = 500 + 7;
int n;
vector<int> g[N];
int wn[N][N][2];

enum {COP, ROB};

/**


win[cop][rob][move] = if the cop can win

if cop == rob:
  win[cop][rob][move] = 1

if move == C:
  if at least one from {win[cop'][rob][R] == 1}:
    win[cop][rob][C] = 1
if move == R:
  if all moves {win[cop][rob'][C] == 1}:
    win[cop][rob][R] = 1

**/

int cnt_bad;
int cnt_good;

void add(int x) {
  assert(x == 0 || x == 1);
  if (x == 0) cnt_bad++;
  if (x == 1) cnt_good++;
}

int C;
int where[N][N];

int start(int nn, bool AE[MAX_N][MAX_N]) {
  n = nn;
  for (int i = 0; i < n; i++) {
    assert(g[i].empty());
  }
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      if (AE[i][j]) {
        assert(AE[j][i]);
        assert(i != j);
        g[i].push_back(j);
      }
    }
    assert(AE[i][i] == 0);
  }
  if (0) {
    cout << "graph = \n";
    for (int i = 0; i < n; i++) {
      for (auto &j : g[i]) {
        cout << "\t\t\t\t\t" << i << " --> " << j << "\n";
      }
    }
  }
  for (int i = 0; i < N; i++) {
    for (int j = 0; j < N; j++) {
      wn[i][j][COP] = wn[i][j][ROB] = 0; /// unsure
    }
  }
  for (int i = 0; i < n; i++) {
    wn[i][i][COP] = wn[i][i][ROB] = 1;
  }
  while (1) {
    bool change = 0;
    int sum = 0;
    for (int cop = 0; cop < n; cop++) {
      for (int rob = 0; rob < n; rob++) {
        if (wn[cop][rob][COP] == 0) {
          /// if it is unsure
          cnt_good = cnt_bad = 0;
          add(wn[cop][rob][ROB]);
          for (auto &vecin : g[cop]) {
            add(wn[vecin][rob][ROB]);
          }
          if (cnt_good >= 1) {
            change = 1;

            assert(wn[cop][rob][COP] == 0);
            wn[cop][rob][COP] = 1;

            int cine = -1;

            if (wn[cop][rob][ROB] == 1) {
              cine = cop;
            }

            for (auto &vecin : g[cop]) {
              if (wn[vecin][rob][ROB] == 1) {
                cine = vecin;
              }
            }
            assert(cine != -1);
            where[cop][rob] = cine;
          }
        } else {
          sum++;
        }
        if (wn[cop][rob][ROB] == 0) {
          /// if it is unsure
          cnt_good = cnt_bad = 0;
          for (auto &vecin : g[rob]) {
            add(wn[cop][vecin][COP]);
          }
          if (cnt_bad == 0) {
            change = 1;
            wn[cop][rob][ROB] = 1;
          }
        } else {
          sum++;
        }
      }
    }
    ///cout << "sum = " << sum << ", " << change << "\n";
    if (!change) {
      break;
    }
  }

  for (int cop = 0; cop < n; cop++) {
    bool good = 1;
    for (int rob = 0; rob < n; rob++) {
      assert(wn[cop][rob][COP] == 0 || wn[cop][rob][COP] == 1);
      assert(wn[cop][rob][ROB] == 0 || wn[cop][rob][ROB] == 1);
      good &= (wn[cop][rob][COP] == 1);
    }
    if (good) {
      return cop;
    }
  }
  return -1;
}

int nextMove(int R) {
  assert(wn[C][R][COP] == 1);

  int new_cop = where[C][R];
  assert(new_cop != -1);
  C = new_cop;
  return C;
}

• Subtask 1: 16 / 16
• Subtask 2: 14 / 14
• Subtask 3: 30 / 30
• Subtask 4: 0 / 40