Problem p02376 (C++) — buggy submission, verdict: Runtime Error

#define _CRT_SECURE_NO_WARNINGS
// #define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
// #define int ll
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> pii;
#define all(c) begin(c), end(c)
#define range(i, a, b) for (ll i = a; i < ll(b); i++)
#define rep(i, b) range(i, 0, b)
#define rangei(i, a, b) for (ll a = a; i <= ll(b); i++)
#define repi(i, b) rangei(i, 1, b)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define mt make_tuple
template <class T> ostream &operator<<(ostream &os, vector<T> const &);
template <int n, class... T>
typename enable_if<(n >= sizeof...(T))>::type _ot(ostream &,
                                                  tuple<T...> const &) {}
template <int n, class... T>
typename enable_if<(n < sizeof...(T))>::type _ot(ostream &os,
                                                 tuple<T...> const &t) {
  os << (n == 0 ? "" : " ") << get<n>(t);
  _ot<n + 1>(os, t);
}
template <class... T> ostream &operator<<(ostream &os, tuple<T...> const &t) {
  _ot<0>(os, t);
  return os;
}
template <class T, class U>
ostream &operator<<(ostream &os, pair<T, U> const &p) {
  return os << "(" << p.first << ", " << p.second << ") ";
}
template <class T> ostream &operator<<(ostream &os, vector<T> const &v) {
  rep(i, v.size()) os << v[i] << (i + 1 == (int)v.size() ? "" : " ");
  return os;
}
#ifdef DEBUG
#define dump(...)                                                              \\
  (cerr << #__VA_ARGS__ << " = " << mt(__VA_ARGS__) << " [" << __LINE__ << "]" \\
        << endl)
#else
#define dump(...)
#endif
void fastios() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  // #define endl '\\n'
}
template <class T> size_t uniq(vector<T> &v) {
  sort(v.begin(), v.end());
  v.erase(unique(v.begin(), v.end()), v.end());
  return v.size();
}
template <class T> size_t uniq(T *l, size_t n) {
  sort(l, l + n);
  return unique(l, l + n) - l;
}
#define mems(arr, val) memset(arr, val, sizeof(arr));
int const mod = 1000000007;
int const inf = numeric_limits<int>::max() / 8;

typedef int Capacity;
struct Edge {
  int src, dst;
  Capacity cap;
  Edge(int src_, int dst_, int cap_) : src(src_), dst(dst_), cap(cap_) {}
};
typedef vector<Edge> Edges;
typedef vector<Edges> Graph;
typedef vector<int> Array;
typedef vector<Array> Matrix;

template <class Capacity = int> struct max_flow {
  typedef vector<vector<Capacity>> Matrix;
  size_t n;
  Matrix cap;
  vector<bool> vis;
  Capacity res;
  max_flow(const int s, const int t, const Graph &g)
      : n(g.size()), cap(n, Array(n)) {
    for (size_t i = 0; i < g.size(); i++) {
      for (size_t j = 0; j < g[i].size(); j++) {
        int u = g[i][j].src, v = g[i][j].dst;
        cap[u][v] = g[i][j].cap;
      }
    }
    res = solve(s, t);
  }
  Capacity augment(const int v, const int t, Capacity lim) {
    vis[v] = true;
    if (v == t)
      return lim;
    for (size_t i = 0; i < n; i++) {
      if (vis[i] || cap[v][i] == 0)
        continue;
      Capacity f = augment(i, t, min(lim, cap[v][i]));
      cap[v][i] -= f, cap[i][v] += f;
      if (f)
        return f;
    }
    return 0;
  }
  Capacity solve(const int s, const int t) {
    Capacity res = 0, f = -1;
    while (f)
      vis.assign(n, false), res += (f = augment(s, t, inf));
    return res;
  }
};

int main() {
  int N, M;
  cin >> N >> M;
  Graph g(N);
  rep(i, M) {
    int a, b, c;
    cin >> a >> b >> c;
    g[a].eb(a, b, c);
  }
  cout << max_flow<>(0, N - 1, g).res << endl;
}

Error: 0

Fixed submission:

#define _CRT_SECURE_NO_WARNINGS
// #define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
// #define int ll
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> pii;
#define all(c) begin(c), end(c)
#define range(i, a, b) for (ll i = a; i < ll(b); i++)
#define rep(i, b) range(i, 0, b)
#define rangei(i, a, b) for (ll a = a; i <= ll(b); i++)
#define repi(i, b) rangei(i, 1, b)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define mt make_tuple
template <class T> ostream &operator<<(ostream &os, vector<T> const &);
template <int n, class... T>
typename enable_if<(n >= sizeof...(T))>::type _ot(ostream &,
                                                  tuple<T...> const &) {}
template <int n, class... T>
typename enable_if<(n < sizeof...(T))>::type _ot(ostream &os,
                                                 tuple<T...> const &t) {
  os << (n == 0 ? "" : " ") << get<n>(t);
  _ot<n + 1>(os, t);
}
template <class... T> ostream &operator<<(ostream &os, tuple<T...> const &t) {
  _ot<0>(os, t);
  return os;
}
template <class T, class U>
ostream &operator<<(ostream &os, pair<T, U> const &p) {
  return os << "(" << p.first << ", " << p.second << ") ";
}
template <class T> ostream &operator<<(ostream &os, vector<T> const &v) {
  rep(i, v.size()) os << v[i] << (i + 1 == (int)v.size() ? "" : " ");
  return os;
}
#ifdef DEBUG
#define dump(...)                                                              \\
  (cerr << #__VA_ARGS__ << " = " << mt(__VA_ARGS__) << " [" << __LINE__ << "]" \\
        << endl)
#else
#define dump(...)
#endif
void fastios() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  // #define endl '\\n'
}
template <class T> size_t uniq(vector<T> &v) {
  sort(v.begin(), v.end());
  v.erase(unique(v.begin(), v.end()), v.end());
  return v.size();
}
template <class T> size_t uniq(T *l, size_t n) {
  sort(l, l + n);
  return unique(l, l + n) - l;
}
#define mems(arr, val) memset(arr, val, sizeof(arr));
int const mod = 1000000007;
int const inf = numeric_limits<int>::max() / 8;

typedef int Capacity;
struct Edge {
  int src, dst;
  Capacity cap;
  Edge(int src_, int dst_, int cap_) : src(src_), dst(dst_), cap(cap_) {}
};
typedef vector<Edge> Edges;
typedef vector<Edges> Graph;
typedef vector<int> Array;
typedef vector<Array> Matrix;

template <class Capacity = int> struct max_flow {
  typedef vector<vector<Capacity>> Matrix;
  size_t n;
  Matrix cap, flow;
  vector<bool> vis;
  Capacity res;
  max_flow(const int s, const int t, const Graph &g)
      : n(g.size()), cap(n, Array(n)), flow(n, Array(n)) {
    for (size_t i = 0; i < g.size(); i++) {
      for (size_t j = 0; j < g[i].size(); j++) {
        int u = g[i][j].src, v = g[i][j].dst;
        Capacity c = g[i][j].cap;
        cap[u][v] = cap[v][u] = flow[v][u] = c;
      }
    }
    res = solve(s, t);
  }
  Capacity augment(const int v, const int t, Capacity lim) {
    vis[v] = true;
    if (v == t)
      return lim;
    for (size_t i = 0; i < n; i++) {
      assert(flow[i][v] <= cap[i][v]);
      assert(flow[v][i] <= cap[v][i]);
      assert(flow[i][v] + flow[v][i] == cap[i][v]);
      if (vis[i] || cap[v][i] <= flow[v][i])
        continue;
      Capacity f = augment(i, t, min(lim, cap[v][i] - flow[v][i]));
      flow[v][i] += f, flow[i][v] -= f;
      if (f)
        return f;
    }
    return 0;
  }
  Capacity solve(const int s, const int t) {
    Capacity res = 0, f = -1;
    while (f)
      vis.assign(n, false), res += (f = augment(s, t, inf));
    return res;
  }
};

int main() {
  int N, M;
  cin >> N >> M;
  Graph g(N);
  rep(i, M) {
    int a, b, c;
    cin >> a >> b >> c;
    g[a].eb(a, b, c);
  }
  cout << max_flow<>(0, N - 1, g).res << endl;
}