Problem p02704 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
using namespace std;
typedef unsigned long long ull;
const int N = 505;
int s[N], t[N];
bool visr[N], visc[N];
ull a[N][N], u[N], v[N], b[N], c[N];
int n;
int main() {
  ull one = 1;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++)
    scanf("%d", &s[i]);
  for (int i = 1; i <= n; i++)
    scanf("%d", &t[i]);
  for (int i = 1; i <= n; i++)
    scanf("%llu", &u[i]);
  for (int i = 1; i <= n; i++)
    scanf("%llu", &v[i]);
  for (ull k = 0; k < 64; k++) {
    memset(visr, false, sizeof(visr));
    memset(visc, false, sizeof(visc));
    vector<int> r, c;
    for (int i = 1; i <= n; i++) {
      if (s[i] == 0)
        r.push_back(i);
      if (t[i] == 0)
        c.push_back(i);
    }
    for (int i = 1; i <= n; i++)
      for (int j = 1; j <= n; j++) {
        if (s[i] == 0 && (u[i] >> k & 1) || t[j] == 0 && (v[j] >> k & 1) ||
            s[i] == 1 && (u[i] >> k & 1) && t[j] == 1 && (v[j] >> k & 1) &&
                !(visr[i] && visc[j]))
          a[i][j] |= one << k, visr[i] = visc[j] = true;
      }
    bool f1 = false, f2 = false;
    int p1 = 0, p2 = 0;
    for (int i = 1; i <= n; i++)
      if ((u[i] >> k & 1) && s[i] == 1 && !visr[i] && c.size()) {
        f1 = true;
        a[i][c[p2]] |= one << k;
        p2++;
        if (p2 == c.size())
          p2 = 0;
      }
    for (int i = 1; i <= n; i++)
      if ((v[i] >> k & 1) && t[i] == 1 && !visc[i] && r.size()) {
        f2 = true;
        a[r[p1]][i] |= one << k;
        p1++;
        if (p1 == r.size())
          p1 = 0;
      }
    assert(!(f1 && f2));
  }
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= n; j++) {
      if (s[i])
        b[i] |= a[i][j];
      else
        b[i] &= a[i][j];
      if (t[j])
        c[j] |= a[i][j];
      else
        c[j] &= a[i][j];
      if (j == 1)
        b[i] = a[i][j];
      if (i == 1)
        c[j] = a[i][j];
    }
  for (int i = 1; i <= n; i++)
    if (u[i] != b[i] || v[i] != c[i]) {
      printf("-1\\n");
      return 0;
    }
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= n; j++)
      printf(j == n ? "%llu\\n" : "%llu ", a[i][j]);
}


Error: 0

Fixed submission:

#include <bits/stdc++.h>
using namespace std;
typedef unsigned long long ull;
const int N = 505;
int s[N], t[N];
bool visr[N], visc[N];
ull a[N][N], u[N], v[N], b[N], c[N];
int n;
int main() {
  ull one = 1;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++)
    scanf("%d", &s[i]);
  for (int i = 1; i <= n; i++)
    scanf("%d", &t[i]);
  for (int i = 1; i <= n; i++)
    scanf("%llu", &u[i]);
  for (int i = 1; i <= n; i++)
    scanf("%llu", &v[i]);
  vector<int> r, c;
  for (int i = 1; i <= n; i++) {
    if (s[i] == 0)
      r.push_back(i);
    if (t[i] == 0)
      c.push_back(i);
  }
  for (ull k = 0; k < 64; k++) {
    memset(visr, false, sizeof(visr));
    memset(visc, false, sizeof(visc));
    for (int i = 1; i <= n; i++)
      for (int j = 1; j <= n; j++) {
        if (s[i] == 0 && (u[i] >> k & 1) || t[j] == 0 && (v[j] >> k & 1) ||
            s[i] == 1 && (u[i] >> k & 1) && t[j] == 1 && (v[j] >> k & 1) &&
                !(visr[i] && visc[j]))
          a[i][j] |= one << k, visr[i] = visc[j] = true;
      }
    bool f1 = false, f2 = false;
    int p1 = 0, p2 = 0;
    for (int i = 1; i <= n; i++)
      if ((u[i] >> k & 1) && s[i] == 1 && !visr[i] && c.size()) {
        f1 = true;
        a[i][c[p2]] |= one << k;
        p2++;
        if (p2 == c.size())
          p2 = 0;
      }
    for (int i = 1; i <= n; i++)
      if ((v[i] >> k & 1) && t[i] == 1 && !visc[i] && r.size()) {
        f2 = true;
        a[r[p1]][i] |= one << k;
        p1++;
        if (p1 == r.size())
          p1 = 0;
      }
    assert(!(f1 && f2));
  }
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= n; j++) {
      if (s[i])
        b[i] |= a[i][j];
      else
        b[i] &= a[i][j];
      if (t[j])
        c[j] |= a[i][j];
      else
        c[j] &= a[i][j];
      if (j == 1)
        b[i] = a[i][j];
      if (i == 1)
        c[j] = a[i][j];
    }
  for (int i = 1; i <= n; i++)
    if (u[i] != b[i] || v[i] != c[i]) {
      printf("-1\\n");
      return 0;
    }
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= n; j++)
      printf(j == n ? "%llu\\n" : "%llu ", a[i][j]);
}