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

#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (ll i = 0; i < n; i++)
#define repl(i, l, r) for (ll i = (l); i < (r); i++)
#define per(i, n) for (ll i = n - 1; i >= 0; i--)
#define perl(i, r, l) for (ll i = r - 1; i >= l; i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define all(x) (x).begin(), (x).end()
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vector<ll>>;
const ll MOD = 1000000007;
const ll MOD9 = 998244353;
const int inf = 1e9 + 10;
const ll INF = 4e18;
const ll dy[8] = {1, 0, -1, 0, 1, 1, -1, -1};
const ll dx[8] = {0, -1, 0, 1, 1, -1, 1, -1};
using Graph = vector<vector<int>>;
double nCk(int n, int k) {
  double res = 1.0;
  for (int i = 0; i < n; i++) {
    res *= 0.5;
  }
  for (int i = 0; i < k; i++) {
    res *= (double)(n - i);
    res /= (double)(k - i);
  }
  return res;
}
struct edge {
  ll to, cost;
};
typedef pair<ll, ll> P;
struct graph {
  ll V;
  vector<vector<edge>> G;
  vector<ll> d;

  graph(ll n) { init(n); }

  void init(ll n) {
    V = n;
    G.resize(V);
    d.resize(V);
    rep(i, V) { d[i] = INF; }
  }

  void add_edge(ll s, ll t, ll cost) {
    edge e;
    e.to = t, e.cost = cost;
    G[s].push_back(e);
  }

  void dijkstra(ll s) {
    rep(i, V) { d[i] = INF; }
    d[s] = 0;
    priority_queue<P, vector<P>, greater<P>> que;
    que.push(P(0, s));
    while (!que.empty()) {
      P p = que.top();
      que.pop();
      ll v = p.second;
      if (d[v] < p.first)
        continue;
      for (auto e : G[v]) {
        if (d[e.to] > d[v] + e.cost) {
          d[e.to] = d[v] + e.cost;
          que.push(P(d[e.to], e.to));
        }
      }
    }
  }
};
class UnionFind {
public:
  int par[100005];
  int depth[100005];
  int nGroup[100005];

  UnionFind(int n) { init(n); }

  void init(int n) {
    for (int i = 0; i < n; i++) {
      par[i] = i;
      depth[i] = 0;
      nGroup[i] = 1;
    }
  }

  int root(int x) {
    if (par[x] == x) {
      return x;
    } else {
      return par[x] = root(par[x]);
    }
  }

  bool same(int x, int y) { return root(x) == root(y); }

  void unite(int x, int y) {
    x = root(x);
    y = root(y);
    if (x == y)
      return;

    if (depth[x] < depth[y]) {
      par[x] = y;
      nGroup[y] += nGroup[x];
      nGroup[x] = 0;
    } else {
      par[y] = x;
      nGroup[x] += nGroup[y];
      nGroup[y] = 0;
      if (depth[x] == depth[y])
        depth[x]++;
    }
  }
};
const ll MAX = 510000;
ll fac[MAX], finv[MAX], inv[MAX];

// テーブルを作る前処理
void COMinit() {
  fac[0] = fac[1] = 1;
  finv[0] = finv[1] = 1;
  inv[1] = 1;
  for (int i = 2; i < MAX; i++) {
    fac[i] = fac[i - 1] * i % MOD;
    inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
    finv[i] = finv[i - 1] * inv[i] % MOD;
  }
}

// 二項係数計算
ll COM(ll n, ll k) {
  if (n < k)
    return 0;
  if (n < 0 || k < 0)
    return 0;
  return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}
ll n, m, q, ca = 0, ans = 0;
vector<ll> a, b, c, d;
void f(vector<ll> &A) {
  if ((ll)A.size() == n) {
    ca = 0;
    rep(i, q) {
      if (A.at(b[i] - 1) - A.at(a[i] - 1) == c[i]) {
        ca += d[i];
      }
    }
    ans = max(ans, ca);
    return;
  }
  ll aa;
  if (A.empty())
    aa = 0;
  else {
    aa = A.back();
  }
  for (ll i = aa; i < m; i++) {
    A.pb(i);
    f(A);
    A.pop_back();
  }
}
int main() {
  cin >> n >> m >> q;
  a.resize(q), b.resize(q), c.resize(q), d.resize(q);
  rep(i, q) {
    cin >> a[i] >> b[i] >> c[i] >> d[i];
    // cout << a[i] << b[i] << c[i] << d[i] << endl;
  }
  vector<ll> A;
  f(A);
  cout << ans << endl;
}


Error: -11

Fixed submission:

#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (ll i = 0; i < n; i++)
#define repl(i, l, r) for (ll i = (l); i < (r); i++)
#define per(i, n) for (ll i = n - 1; i >= 0; i--)
#define perl(i, r, l) for (ll i = r - 1; i >= l; i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define all(x) (x).begin(), (x).end()
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vector<ll>>;
const ll MOD = 1000000007;
const ll MOD9 = 998244353;
const int inf = 1e9 + 10;
const ll INF = 4e18;
const ll dy[8] = {1, 0, -1, 0, 1, 1, -1, -1};
const ll dx[8] = {0, -1, 0, 1, 1, -1, 1, -1};
using Graph = vector<vector<int>>;
double nCk(int n, int k) {
  double res = 1.0;
  for (int i = 0; i < n; i++) {
    res *= 0.5;
  }
  for (int i = 0; i < k; i++) {
    res *= (double)(n - i);
    res /= (double)(k - i);
  }
  return res;
}
struct edge {
  ll to, cost;
};
typedef pair<ll, ll> P;
struct graph {
  ll V;
  vector<vector<edge>> G;
  vector<ll> d;

  graph(ll n) { init(n); }

  void init(ll n) {
    V = n;
    G.resize(V);
    d.resize(V);
    rep(i, V) { d[i] = INF; }
  }

  void add_edge(ll s, ll t, ll cost) {
    edge e;
    e.to = t, e.cost = cost;
    G[s].push_back(e);
  }

  void dijkstra(ll s) {
    rep(i, V) { d[i] = INF; }
    d[s] = 0;
    priority_queue<P, vector<P>, greater<P>> que;
    que.push(P(0, s));
    while (!que.empty()) {
      P p = que.top();
      que.pop();
      ll v = p.second;
      if (d[v] < p.first)
        continue;
      for (auto e : G[v]) {
        if (d[e.to] > d[v] + e.cost) {
          d[e.to] = d[v] + e.cost;
          que.push(P(d[e.to], e.to));
        }
      }
    }
  }
};
class UnionFind {
public:
  int par[100005];
  int depth[100005];
  int nGroup[100005];

  UnionFind(int n) { init(n); }

  void init(int n) {
    for (int i = 0; i < n; i++) {
      par[i] = i;
      depth[i] = 0;
      nGroup[i] = 1;
    }
  }

  int root(int x) {
    if (par[x] == x) {
      return x;
    } else {
      return par[x] = root(par[x]);
    }
  }

  bool same(int x, int y) { return root(x) == root(y); }

  void unite(int x, int y) {
    x = root(x);
    y = root(y);
    if (x == y)
      return;

    if (depth[x] < depth[y]) {
      par[x] = y;
      nGroup[y] += nGroup[x];
      nGroup[x] = 0;
    } else {
      par[y] = x;
      nGroup[x] += nGroup[y];
      nGroup[y] = 0;
      if (depth[x] == depth[y])
        depth[x]++;
    }
  }
};
const ll MAX = 510000;
ll fac[MAX], finv[MAX], inv[MAX];

// テーブルを作る前処理
void COMinit() {
  fac[0] = fac[1] = 1;
  finv[0] = finv[1] = 1;
  inv[1] = 1;
  for (int i = 2; i < MAX; i++) {
    fac[i] = fac[i - 1] * i % MOD;
    inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
    finv[i] = finv[i - 1] * inv[i] % MOD;
  }
}

// 二項係数計算
ll COM(ll n, ll k) {
  if (n < k)
    return 0;
  if (n < 0 || k < 0)
    return 0;
  return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}
ll n, m, q, a[100], b[100], c[100], d[100], ca = 0, ans = 0;
void f(ll h, ll k, ll p) {
  if (k == n) {
    ca = 0;
    string s = to_string(h);
    rep(i, q) {
      if (s.at(b[i] - 1) - '0' - s.at(a[i] - 1) + '0' == c[i]) {
        ca += d[i];
      }
    }
    ans = max(ans, ca);
  }
  for (ll i = p; i <= m; p++) {
    f(h * 10 + i, k + 1, i);
  }
}
int main() {
  cin >> n >> m >> q;
  rep(i, q) { cin >> a[i] >> b[i] >> c[i] >> d[i]; }
  f(0, 0, 1);
  cout << ans << endl;
}