Problem p02695 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
// #include <boost/multiprecision/cpp_int.hpp>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
#pragma GCC optimize("O3")
#define REP(i, n) for (int i = 0; i < n; i++)
#define REPP(i, n) for (int i = 1; i <= n; i++)
#define ALL(obj) (obj).begin(), (obj).end()
#define EPS (1e-9)
#define INF (1e17)
#define PI (acos(-1))
// const double PI = acos(-1);
// const double EPS = 1e-15;
// long long INF=(long long)1E17;
#define i_7 (long long)(1e9 + 7)
// #define i_7 998'244'353
long mod(long a) {
  long long c = a % i_7;
  if (c >= 0)
    return c;
  return c + i_7;
}
long long po(long a, long b) {
  if (b == 0) {
    return 1;
  }

  long long z = po(a, b / 2);
  z = mod(z * z);
  if (b % 2 != 0) {
    z = mod(a * z);
  }
  return z;
}

bool prime_(int n) {
  if (n == 1) {
    return false;
  } else if (n == 2) {
    return true;
  } else {
    for (int i = 2; i <= std::sqrt(n); i++) {
      if (n % i == 0) {
        return false;
      }
    }
    return true;
  }
}

long long gcd_(long long a, long long b) {
  if (a < b) {
    std::swap(a, b);
  }
  if (a % b == 0) {
    return b;
  } else {
    return gcd_(b, a % b);
  }
}

long long lcm_(long long x, long long y) { return (x / gcd_(x, y)) * y; }

using namespace std;
// using namespace boost::multiprecision;
// using namespace __gnu_pbds;

int n, m, q;
int a[50], b[50], c[50];
long long d[50];

long long dfs(vector<int> &now, int index = 0, int mx = 1) {
  long long res = 0;
  if (index == n) {
    REP(i, q) {
      if (now[b[i]] - now[a[i]] == c[i])
        res += d[i];
    }
    return res;
  }
  for (int v = mx; v <= m; v++) {
    now[index] = v;
    res = max(res, dfs(now, index + 1, v));
    now[index] = 0;
  }
  return res;
}
int main() {
  // using namespace std;
  cin >> n >> m >> q;
  REP(i, q) {
    cin >> a[i] >> b[i] >> c[i] >> d[i];
    a[i]--;
    b[i]--;
  }
  vector<int> now(n, 0);
  long long ans = dfs(now);
  cout << ans << endl;
  return 0;
}


Error: 110

Fixed submission:

#include <bits/stdc++.h>
// #include <boost/multiprecision/cpp_int.hpp>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
#pragma GCC optimize("O3")
#define REP(i, n) for (int i = 0; i < n; i++)
#define REPP(i, n) for (int i = 1; i <= n; i++)
#define ALL(obj) (obj).begin(), (obj).end()
#define EPS (1e-9)
#define INF (1e17)
#define PI (acos(-1))
// const double PI = acos(-1);
// const double EPS = 1e-15;
// long long INF=(long long)1E17;
#define i_7 (long long)(1e9 + 7)
// #define i_7 998'244'353
long mod(long a) {
  long long c = a % i_7;
  if (c >= 0)
    return c;
  return c + i_7;
}
long long po(long a, long b) {
  if (b == 0) {
    return 1;
  }

  long long z = po(a, b / 2);
  z = mod(z * z);
  if (b % 2 != 0) {
    z = mod(a * z);
  }
  return z;
}

bool prime_(int n) {
  if (n == 1) {
    return false;
  } else if (n == 2) {
    return true;
  } else {
    for (int i = 2; i <= std::sqrt(n); i++) {
      if (n % i == 0) {
        return false;
      }
    }
    return true;
  }
}

long long gcd_(long long a, long long b) {
  if (a < b) {
    std::swap(a, b);
  }
  if (a % b == 0) {
    return b;
  } else {
    return gcd_(b, a % b);
  }
}

long long lcm_(long long x, long long y) { return (x / gcd_(x, y)) * y; }

using namespace std;
// using namespace boost::multiprecision;
// using namespace __gnu_pbds;

int n, m, q;
int a[50], b[50], c[50];
long long d[50];

long long dfs(vector<int> &now, int index = 0, int mx = 1) {
  long long res = 0;
  if (index == n) {
    REP(i, q) {
      if (now[b[i]] - now[a[i]] == c[i])
        res += d[i];
    }
    return res;
  }
  for (int v = mx; v <= m; v++) {
    now[index] = v;
    res = max(res, dfs(now, index + 1, v));
    now[index] = 0;
  }
  return res;
}
int main() {
  // using namespace std;
  cin >> n >> m >> q;
  REP(i, q) {
    cin >> a[i] >> b[i] >> c[i] >> d[i];
    a[i]--;
    b[i]--;
  }
  vector<int> now = vector<int>(n, 0);
  long long ans = dfs(now);
  return ans;
  return 0;
}