Problem p01139 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second
#define repl(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define repr(i, n) for (int i = (int)(n - 1); i >= 0; i--)
#define rep(i, n) repl(i, 0, n)
#define each(itr, v) for (auto itr : v)
#define pb(s) push_back(s)
#define all(x) (x).begin(), (x).end()
#define dbg(x) cout << #x " = " << x << endl
#define print(x) cout << x << endl
#define maxch(x, y) x = max(x, y)
#define minch(x, y) x = min(x, y)
#define uni(x) x.erase(unique(all(x)), x.end())
#define exist(x, y) (find(all(x), y) != x.end())
#define bcnt(x) bitset<32>(x).count()

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> P;
typedef pair<P, int> PPI;
typedef pair<int, P> PIP;
typedef pair<ll, ll> PL;
typedef pair<P, ll> PPL;
typedef set<int> S;

#define INF INT_MAX / 3
#define MAX_N 1000000001

int w, h;
vector<string> island(51);
P land[51][51];
int dd[] = {1, 0, -1, 0, 1};

bool range(int y, int x) { return 0 <= y && y < h && 0 <= x && x < w; }

void dfs(int y, int x, bool b) {
  if (b)
    land[y][x].fi = 1;
  else
    land[y][x].se = 1;

  int yy, xx;
  rep(i, 4) {
    yy = y + dd[i], xx = x + dd[i + 1];
    if (range(yy, xx)) {
      if (b) {
        if (island[yy][xx] == '.' && land[yy][xx].fi == 0)
          dfs(yy, xx, b);
      } else {
        if (island[yy][xx] == '.' && land[yy][xx].se == 0)
          dfs(yy, xx, b);
      }
    }
  }
}

int main() {
  cin.sync_with_stdio(false);
  while (cin >> w >> h, w | h) {
    rep(i, h) cin >> island[i];
    rep(i, h) rep(j, w) land[i][j] = P(0, 0);
    rep(i, h) rep(j, w) {
      if (island[i][j] != '.')
        land[i][j] = P(1, 1), dfs(i, j, island[i][j] == 'B');
    }

    int black = 0, white = 0;
    rep(i, h) rep(j, w) {
      if (land[i][j].fi == 1 && land[i][j].se == 0)
        black++;
      if (land[i][j].fi == 0 && land[i][j].se == 1)
        white++;
    }

    cout << black << " " << white << endl;
  }

  return 0;
}

Error: 0

Fixed submission:

#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second
#define repl(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define repr(i, n) for (int i = (int)(n - 1); i >= 0; i--)
#define rep(i, n) repl(i, 0, n)
#define each(itr, v) for (auto itr : v)
#define pb(s) push_back(s)
#define all(x) (x).begin(), (x).end()
#define dbg(x) cout << #x " = " << x << endl
#define print(x) cout << x << endl
#define maxch(x, y) x = max(x, y)
#define minch(x, y) x = min(x, y)
#define uni(x) x.erase(unique(all(x)), x.end())
#define exist(x, y) (find(all(x), y) != x.end())
#define bcnt(x) bitset<32>(x).count()

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> P;
typedef pair<P, int> PPI;
typedef pair<int, P> PIP;
typedef pair<ll, ll> PL;
typedef pair<P, ll> PPL;
typedef set<int> S;

#define INF INT_MAX / 3
#define MAX_N 1000000001

int w, h;
vector<string> island(50);
P land[50][50];
int dd[] = {1, 0, -1, 0, 1};

bool range(int y, int x) { return 0 <= y && y <= h && 0 <= x && x <= w; }

void dfs(int y, int x, bool b) {
  if (b)
    land[y][x].fi = 1;
  else
    land[y][x].se = 1;

  int yy, xx;
  rep(i, 4) {
    yy = y + dd[i], xx = x + dd[i + 1];
    if (range(yy, xx)) {
      if (b) {
        if (island[yy][xx] == '.' && land[yy][xx].fi == 0)
          dfs(yy, xx, b);
      } else {
        if (island[yy][xx] == '.' && land[yy][xx].se == 0)
          dfs(yy, xx, b);
      }
    }
  }
}

int main() {
  cin.sync_with_stdio(false);
  while (cin >> w >> h, w | h) {
    rep(i, h) cin >> island[i];
    rep(i, h) rep(j, w) land[i][j] = P(0, 0);
    rep(i, h) rep(j, w) {
      if (island[i][j] != '.')
        land[i][j] = P(1, 1), dfs(i, j, island[i][j] == 'B');
    }

    int black = 0, white = 0;
    rep(i, h) rep(j, w) {
      if (land[i][j].fi == 1 && land[i][j].se == 0)
        black++;
      if (land[i][j].fi == 0 && land[i][j].se == 1)
        white++;
    }

    cout << black << " " << white << endl;
  }

  return 0;
}