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

#include <algorithm>
#include <bits/stdc++.h>
#include <cmath>
#include <iostream>
#include <string>
#include <unordered_map>
#include <unordered_set>
using namespace std;
#define ll long long
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define FOR(i, a, b) for (ll i = (a); i < (b); i++)
#define FORR(i, a, b) for (ll i = (a); i <= (b); i++)
#define repR(i, n) for (ll i = n; i >= 0; i--)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define F first
#define S second
#define pb push_back
#define pu push
#define COUT(x) cout << (x) << endl
#define PQ priority_queue<ll>
#define PQR priority_queue<ll, vector<ll>, greater<ll>>
#define YES(n) cout << ((n) ? "YES" : "NO") << endl
#define Yes(n) cout << ((n) ? "Yes" : "No") << endl
#define mp make_pair
#define maxs(x, y) (x = max(x, y))
#define mins(x, y) (x = min(x, y))
#define sz(x) (ll)(x).size()
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const ll MOD = 1000000007LL;
const ll INF = 1LL << 60;
using vll = vector<ll>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvll = vector<vll>;
using vstr = vector<string>;
using pll = pair<ll, ll>;
using vc = vector<char>;
using vvc = vector<vc>;
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
ll dx[4] = {0, 1, 0, -1};
ll dy[4] = {1, 0, -1, 0};
ll n, m, q;
vll a, b, c, d;
ll ans = 0;
void dfs(vll A) {
  if (sz(A) == n + 1) {
    ll now = 0;
    rep(i, q) {
      if (A[b[i]] - A[a[i]] == c[i])
        now += d[i];
    }
    ans = max(ans, now);
    return;
  }
  A.pb(A.back());
  while (A.back() <= m) {
    dfs(A);
    A.back()++;
  }
}
int main() {
  cin >> n >> m >> q;
  a = b = c = d = vll(q);
  rep(i, q) { cin >> a[i] >> b[i] >> c[i] >> d[i]; }
  dfs(vector<ll>(1, 1));
  COUT(ans);
}


Error: -11

Fixed submission:

#include <algorithm>
#include <bits/stdc++.h>
#include <cmath>
#include <iostream>
#include <string>
#include <unordered_map>
#include <unordered_set>
using namespace std;
#define ll long long
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define FOR(i, a, b) for (ll i = (a); i < (b); i++)
#define FORR(i, a, b) for (ll i = (a); i <= (b); i++)
#define repR(i, n) for (ll i = n; i >= 0; i--)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define F first
#define S second
#define pb push_back
#define pu push
#define COUT(x) cout << (x) << endl
#define PQ priority_queue<ll>
#define PQR priority_queue<ll, vector<ll>, greater<ll>>
#define YES(n) cout << ((n) ? "YES" : "NO") << endl
#define Yes(n) cout << ((n) ? "Yes" : "No") << endl
#define mp make_pair
#define maxs(x, y) (x = max(x, y))
#define mins(x, y) (x = min(x, y))
#define sz(x) (ll)(x).size()
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const ll MOD = 1000000007LL;
const ll INF = 1LL << 60;
using vll = vector<ll>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvll = vector<vll>;
using vstr = vector<string>;
using pll = pair<ll, ll>;
using vc = vector<char>;
using vvc = vector<vc>;
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
ll dx[4] = {0, 1, 0, -1};
ll dy[4] = {1, 0, -1, 0};
ll n, m, q;
vll a(q), b(q), c(q), d(q);
ll ans = 0;
void dfs(vll A) {
  if (sz(a) == n + 1) {
    ll now = 0;
    rep(i, q) {
      if (A[b[i]] - A[a[i]] == c[i])
        now += d[i];
    }
    ans = max(ans, now);
    return;
  }
  A.pb(A.back());
  while (A.back() <= m) {
    dfs(A);
    A.back()++;
  }
}
int main() {
  cin >> n >> m >> q;
  rep(i, q) { cin >> a[i] >> b[i] >> c[i] >> d[i]; }
  dfs(vector<ll>(1, 1));
  COUT(ans);
}