Problem p03450 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <algorithm>
#include <array>
#include <bitset>
#include <cmath>
#include <complex>
#include <cstdio>
#include <deque>
#include <float.h>
#include <functional>
#include <iomanip>
#include <iostream>
#include <limits.h>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdio.h>
#include <string.h>
#include <string>
#include <tuple>
#include <unordered_map>
#include <vector>

using namespace std;
#define int long long

#define I32_MAX 2147483647
#define I64_MAX 9223372036854775807LL
#define I64_MAX2 1223372036854775807LL
#define INF I64_MAX2
#define MOD 1000000007
#define MEM_SIZE 10000
#define DEBUG_OUT true
#define ALL(x) (x).begin(), (x).end()

template <typename T> void DEBUG(T e) {
  if (DEBUG_OUT == false)
    return;
  std::cout << e << " ";
}
template <typename T> void DEBUG(const std::vector<T> &v) {
  if (DEBUG_OUT == false)
    return;
  for (const auto &e : v) {
    std::cout << e << " ";
  }
  std::cout << std::endl;
}
template <typename T> void DEBUG(const std::vector<std::vector<T>> &vv) {
  if (DEBUG_OUT == false)
    return;
  for (const auto &v : vv) {
    DEBUG(v);
  }
}
template <class T, class... Ts> void DEBUG(T d, Ts... e) {
  if (DEBUG_OUT == false)
    return;
  DEBUG(d);
  DEBUG(e...);
}
template <class T> void corner(bool flg, T hoge) {
  if (flg) {
    cout << hoge << endl;
    exit(0);
  }
}
template <typename T1, typename T2> inline bool chmax(T1 &a, T2 b) {
  return a < b && (a = b, true);
}
template <typename T1, typename T2> inline bool chmin(T1 &a, T2 b) {
  return a > b && (a = b, true);
}

//-----CODE------//

template <typename T> struct edge {
  int src, to;
  T cost;

  edge(int to, T cost) : src(-1), to(to), cost(cost) {}

  edge(int src, int to, T cost) : src(src), to(to), cost(cost) {}

  edge &operator=(const int &x) {
    to = x;
    return *this;
  }

  operator int() const { return to; }
};

template <typename T> using Edges = vector<edge<T>>;
template <typename T> using WeightedGraph = vector<Edges<T>>;
using UnWeightedGraph = vector<vector<int>>;
template <typename T> using Matrix = vector<vector<T>>;

bool DFS(int V, int P, int D, WeightedGraph<int> WG, vector<int> &dist) {
  //  if(dist[V] != -1*INF) return 1;
  dist[V] = D;
  bool res = 1;
  //  DEBUG(V,P,D,"\n");
  for (int i = 0; i < WG[V].size(); i++) {
    int nV = WG[V][i].to;
    int nD = D + WG[V][i].cost;

    if (dist[nV] == -INF) {
      dist[nV] = nD;
      res &= DFS(nV, V, nD, WG, dist);
    } else {
      if (nD != dist[nV])
        res = 0;
    }
  }
  return res;
}

void solve(void) {
  int N, M;
  cin >> N >> M;
  WeightedGraph<int> WG(N);
  for (int i = 0; i < M; i++) {
    int A, B, D;
    cin >> A >> B >> D;
    A--;
    B--;
    WG[A].emplace_back(A, B, D);
    WG[B].emplace_back(B, A, -1 * D);
  }
  vector<int> dist(N, -1 * INF);
  bool check = 1;
  for (int i = 0; i < N; i++) {
    if (dist[i] == -1 * INF) {
      check &= DFS(i, -1, 0, WG, dist);
    }
  }
  // DEBUG(dist);
  if (check) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
}
int32_t main(int32_t argc, const char *argv[]) {
  std::ios::sync_with_stdio(false);
  std::cin.tie(0);

  std::cout << std::fixed;
  std::cout << std::setprecision(9);
  solve();

  return 0;
}

Fixed submission:
#include <algorithm>
#include <array>
#include <bitset>
#include <cmath>
#include <complex>
#include <cstdio>
#include <deque>
#include <float.h>
#include <functional>
#include <iomanip>
#include <iostream>
#include <limits.h>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdio.h>
#include <string.h>
#include <string>
#include <tuple>
#include <unordered_map>
#include <vector>

using namespace std;
#define int long long

#define I32_MAX 2147483647
#define I64_MAX 9223372036854775807LL
#define I64_MAX2 1223372036854775807LL
#define INF I64_MAX2
#define MOD 1000000007
#define MEM_SIZE 10000
#define DEBUG_OUT true
#define ALL(x) (x).begin(), (x).end()

template <typename T> void DEBUG(T e) {
  if (DEBUG_OUT == false)
    return;
  std::cout << e << " ";
}
template <typename T> void DEBUG(const std::vector<T> &v) {
  if (DEBUG_OUT == false)
    return;
  for (const auto &e : v) {
    std::cout << e << " ";
  }
  std::cout << std::endl;
}
template <typename T> void DEBUG(const std::vector<std::vector<T>> &vv) {
  if (DEBUG_OUT == false)
    return;
  for (const auto &v : vv) {
    DEBUG(v);
  }
}
template <class T, class... Ts> void DEBUG(T d, Ts... e) {
  if (DEBUG_OUT == false)
    return;
  DEBUG(d);
  DEBUG(e...);
}
template <class T> void corner(bool flg, T hoge) {
  if (flg) {
    cout << hoge << endl;
    exit(0);
  }
}
template <typename T1, typename T2> inline bool chmax(T1 &a, T2 b) {
  return a < b && (a = b, true);
}
template <typename T1, typename T2> inline bool chmin(T1 &a, T2 b) {
  return a > b && (a = b, true);
}

//-----CODE------//

template <typename T> struct edge {
  int src, to;
  T cost;

  edge(int to, T cost) : src(-1), to(to), cost(cost) {}

  edge(int src, int to, T cost) : src(src), to(to), cost(cost) {}

  edge &operator=(const int &x) {
    to = x;
    return *this;
  }

  operator int() const { return to; }
};

template <typename T> using Edges = vector<edge<T>>;
template <typename T> using WeightedGraph = vector<Edges<T>>;
using UnWeightedGraph = vector<vector<int>>;
template <typename T> using Matrix = vector<vector<T>>;

bool DFS(int V, int P, int D, WeightedGraph<int> &WG, vector<int> &dist) {
  //  if(dist[V] != -1*INF) return 1;
  dist[V] = D;
  bool res = 1;
  //  DEBUG(V,P,D,"\n");
  for (int i = 0; i < WG[V].size(); i++) {
    int nV = WG[V][i].to;
    int nD = D + WG[V][i].cost;

    if (dist[nV] == -INF) {
      dist[nV] = nD;
      res &= DFS(nV, V, nD, WG, dist);
    } else {
      if (nD != dist[nV])
        res = 0;
    }
  }
  return res;
}

void solve(void) {
  int N, M;
  cin >> N >> M;
  WeightedGraph<int> WG(N);
  for (int i = 0; i < M; i++) {
    int A, B, D;
    cin >> A >> B >> D;
    A--;
    B--;
    WG[A].emplace_back(A, B, D);
    WG[B].emplace_back(B, A, -1 * D);
  }
  vector<int> dist(N, -1 * INF);
  bool check = 1;
  for (int i = 0; i < N; i++) {
    if (dist[i] == -1 * INF) {
      check &= DFS(i, -1, 0, WG, dist);
    }
  }
  // DEBUG(dist);
  if (check) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
}
int32_t main(int32_t argc, const char *argv[]) {
  std::ios::sync_with_stdio(false);
  std::cin.tie(0);

  std::cout << std::fixed;
  std::cout << std::setprecision(9);
  solve();

  return 0;
}