Problem p02579 (C++) — buggy submission, verdict: Runtime Error


#include <algorithm>
#include <cmath>
#include <cstring>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <vector>

using namespace std;

// Debugging Template
/*  ^^    ^^    ^^    ^^    ^^    ^^    ^^    ^^    ^^    ^^    ^^    ^^    ^^
 * ^^  */

void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\\'' << x << '\\''; }
void __print(const char *x) { cerr << '\\"' << x << '\\"'; }
void __print(const string &x) { cerr << '\\"' << x << '\\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template <typename T, typename V> void __print(const pair<T, V> &x) {
  cerr << '{';
  __print(x.first);
  cerr << ',';
  __print(x.second);
  cerr << '}';
}
template <typename T> void __print(const T &x) {
  int f = 0;
  cerr << '{';
  for (auto &i : x)
    cerr << (f++ ? "," : ""), __print(i);
  cerr << "}";
}
void _print() { cerr << "]\\n"; }
template <typename T, typename... V> void _print(T t, V... v) {
  __print(t);
  if (sizeof...(v))
    cerr << ", ";
  _print(v...);
}
#ifndef ONLINE_JUDGE
#define debug(x...)                                                            \\
  cerr << "[" << #x << "] = [";                                                \\
  _print(x)
#else
#define debug(x...)
#endif

/*  ^^    ^^    ^^    ^^    ^^    ^^    ^^    ^^    ^^    ^^    ^^    ^^    ^^
 * ^^  */
void file_io() {
  freopen("ariprog.in", "r", stdin);
  freopen("ariprog.out", "w", stdout);
}

typedef pair<int, int> pii;
typedef long long ll;

const int V = int(2e5);
const int INF = int(2e9);

char mat[1000][1000];
int mark[1000][1000];
int mark2[1000][1000];
int marks[1000 * 1000];
int h, w, c1, c2, t1, t2;
int group_num = 0;

void solve(int r, int c) {
  if (r < 0 || r >= h || c < 0 || c >= w)
    return;

  if (mark[r][c] != 0)
    return;

  if (mat[r][c] == '#')
    return;

  mark[r][c] = group_num;

  solve(r + 1, c);
  solve(r - 1, c);
  solve(r, c + 1);
  solve(r, c - 1);
}

void solve2(int r, int c) {
  if (r < 0 || r >= h || c < 0 || c >= w)
    return;

  if (mark2[r][c] != 0)
    return;

  if (mat[r][c] == '#')
    return;

  mark2[r][c] = 1;

  for (int i = r - 2; i <= r + 2; ++i)
    for (int j = c - 2; j <= c + 2; ++j)
      solve2(i, j);
}

int main() {

  cin >> h >> w >> c1 >> c2 >> t1 >> t2;
  c1--;
  c2--;
  t1--;
  t2--;

  for (int i = 0; i < h; ++i)
    for (int j = 0; j < w; ++j)
      cin >> mat[i][j];

  for (int i = 0; i < h; ++i) {
    for (int j = 0; j < w; ++j) {
      if (mark[i][j] == 0 && mat[i][j] == '.') {
        group_num++;
        solve(i, j);
      }
    }
  }

  // for (int i=0; i<h; ++i)
  // {
  //     for (int j=0; j<w; ++j)
  //     {
  //         cout << mark[i][j] << " ";
  //     }
  //     cout << endl;
  // }

  if (mark[c1][c2] == mark[t1][t2]) {
    cout << 0 << endl;
    return 0;
  }

  solve2(c1, c2);

  // for (int i=0; i<h; ++i)
  // {
  //     for (int j=0; j<w; ++j)
  //     {
  //         cout << mark2[i][j] << " ";
  //     }
  //     cout << endl;
  // }

  if (mark2[t1][t2] == 0) {
    cout << -1 << endl;
    return 0;
  }

  vector<vector<int>> ls(group_num + 10000);
  set<pair<int, int>> remset;
  for (int i = 0; i < h; ++i) {
    for (int j = 0; j < w; ++j) {
      if (mat[i][j] == '#')
        continue;
      for (int k = i - 2; k <= i + 2; ++k) {
        for (int l = j - 2; l <= j + 2; ++l) {
          if (k < 0 || k >= h || l < 0 || l >= w)
            continue;
          if (mat[k][l] == '#')
            continue;
          if (mark[i][j] == mark[k][l])
            continue;
          int g1 = mark[i][j], g2 = mark[k][l];
          if (remset.count({min(g1, g2), max(g1, g2)}) != 0)
            continue;
          remset.insert({min(g1, g2), max(g1, g2)});
          ls[mark[i][j]].push_back(mark[k][l]);
          ls[mark[k][l]].push_back(mark[i][j]);
        }
      }
    }
  }
  // debug(remset);

  queue<int> Q;
  Q.push(mark[c1][c2]);
  marks[mark[c1][c2]] = 1;
  vector<int> level(group_num + 1);
  level[mark[c1][c2]] = 0;
  while (!Q.empty()) {
    int v = Q.front();
    Q.pop();

    if (v == mark[t1][t2]) {
      // debug(level);
      cout << level[v] << endl;
      return 0;
    }
    for (auto child : ls[v]) {

      if (marks[child])
        continue;
      level[child] = level[v] + 1;
      Q.push(child);
      marks[child] = 1;
    }
  }
}

/*
10 10
1 1
10 10
.#.#.#.#.#
#.#.#.#.#.
.#.#.#.#.#
#.#.#.#.#.
.#.#.#.#.#
#.#.#.#.#.
.#.#.#.#.#
#.#.#.#.#.
.#.#.#.#.#
#.#.#.#.#.
*/

Error: WA

Fixed submission:


#include <algorithm>
#include <cmath>
#include <cstring>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <vector>

using namespace std;

char mat[1000][1000];
int mark[1000][1000];
int mark2[1000][1000];
int markg[1000][1000];
int marks[1000];
int h, w, c1, c2, t1, t2;
int group_num = 0;

void solve(int r, int c) {
  if (r < 0 || r >= h || c < 0 || c >= w)
    return;

  if (mark[r][c] != 0)
    return;

  if (mat[r][c] == '#')
    return;

  mark[r][c] = group_num;

  solve(r + 1, c);
  solve(r - 1, c);
  solve(r, c + 1);
  solve(r, c - 1);
}

void solve2(int r, int c) {
  if (r < 0 || r >= h || c < 0 || c >= w)
    return;

  if (mark2[r][c] != 0)
    return;

  if (mat[r][c] == '#')
    return;

  mark2[r][c] = 1;

  for (int i = r - 2; i <= r + 2; ++i)
    for (int j = c - 2; j <= c + 2; ++j)
      solve2(i, j);
}

int main() {

  cin >> h >> w >> c1 >> c2 >> t1 >> t2;
  c1--;
  c2--;
  t1--;
  t2--;

  for (int i = 0; i < h; ++i)
    for (int j = 0; j < w; ++j)
      cin >> mat[i][j];

  for (int i = 0; i < h; ++i) {
    for (int j = 0; j < w; ++j) {
      if (mark[i][j] == 0 && mat[i][j] == '.') {
        group_num++;
        solve(i, j);
      }
    }
  }

  // for (int i=0; i<h; ++i)
  // {
  //     for (int j=0; j<w; ++j)
  //     {
  //         cout << mark[i][j] << " ";
  //     }
  //     cout << endl;
  // }

  if (mark[c1][c2] == mark[t1][t2]) {
    cout << 0 << endl;
    return 0;
  }

  solve2(c1, c2);

  // for (int i=0; i<h; ++i)
  // {
  //     for (int j=0; j<w; ++j)
  //     {
  //         cout << mark2[i][j] << " ";
  //     }
  //     cout << endl;
  // }

  if (mark2[t1][t2] == 0) {
    cout << -1 << endl;
    return 0;
  }

  vector<vector<int>> ls(group_num + 1);

  for (int i = 0; i < h; ++i) {
    for (int j = 0; j < w; ++j) {
      for (int k = i - 2; k <= i + 2; ++k) {
        for (int l = j - 2; l <= j + 2; ++l) {
          if (k < 0 || k >= h || l < 0 || l >= w)
            continue;
          if (mat[k][l] == '#')
            continue;
          if (mark[i][j] == mark[k][l])
            continue;
          int g1 = mark[i][j], g2 = mark[k][l];
          if (markg[g1][g2])
            continue;
          markg[g1][g2] = 1;
          markg[g2][g1] = 1;
          ls[mark[i][j]].push_back(mark[k][l]);
          ls[mark[k][l]].push_back(mark[i][j]);
        }
      }
    }
  }
  cout << 2 << endl;
  // queue<int> Q;
  // Q.push(mark[c1][c2]);
  // marks[mark[c1][c2]] = 1;
  // vector<int> level(group_num+1);
  // level[mark[c1][c2]]=0;
  // while (!Q.empty())
  // {
  //     int v = Q.front();
  //     Q.pop();

  //     for (auto child : ls[v])
  //     {
  //         if (marks[child]) continue;
  //         Q.push(child);
  //         marks[child] = 1;
  //         level[child] = level[v] + 1;
  //         if (child == mark[t1][2])
  //         {
  //             cout << level[mark[t1][t2]] << endl;
  //             return 0;
  //         }

  //     }

  // }
}