Problem p02655 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x, to) for (x = 0; x < (to); x++)
#define FORR(x, arr) for (auto &x : arr)
#define ITR(x, c) for (__typeof(c.begin()) x = c.begin(); x != c.end(); x++)
#define ALL(a) (a.begin()), (a.end())
#define ZERO(a) memset(a, 0, sizeof(a))
#define MINUS(a) memset(a, 0xff, sizeof(a))
//-------------------------------------------------------

int N, M;
int A[101010], B[101010], C[101010], E[101010];

int SB[101010];
ll SC[101010];
int iscycle[101010];

template <int um> class UF {
public:
  vector<int> par, rank, cnt;
  UF() {
    par = rank = vector<int>(um, 0);
    cnt = vector<int>(um, 1);
    for (int i = 0; i < um; i++)
      par[i] = i;
  }
  void reinit() {
    int i;
    FOR(i, um) rank[i] = 0, cnt[i] = 1, par[i] = i;
  }
  int operator[](int x) {
    return (par[x] == x) ? (x) : (par[x] = operator[](par[x]));
  }
  int count(int x) { return cnt[operator[](x)]; }
  int operator()(int x, int y) {
    if ((x = operator[](x)) == (y = operator[](y)))
      return x;
    cnt[y] = cnt[x] = cnt[x] + cnt[y];
    if (rank[x] > rank[y])
      return par[x] = y;
    rank[x] += rank[x] == rank[y];
    return par[y] = x;
  }
};
UF<101010> uf;

void solve() {
  int i, j, k, l, r, x, y;
  string s;

  cin >> N >> M;
  int P = 0, X = 0, Y, Z;
  FOR(i, M) {
    cin >> A[i] >> B[i] >> C[i];
    A[i]--;
    B[i]--;
    E[A[i]]++;
    E[B[i]]++;
    if (uf[A[i]] != uf[B[i]]) {
      SB[uf[A[i]]] = SB[uf[B[i]]] = SB[uf[A[i]]] + SB[uf[B[i]]];
      SC[uf[A[i]]] = SC[uf[B[i]]] = SC[uf[A[i]]] + SC[uf[B[i]]];
      uf(A[i], B[i]);
    }
    if (A[i] != B[i])
      P++;
    SB[uf[A[i]]]++;
    SC[uf[A[i]]] += C[i] - 1;
  }

  FOR(i, N) iscycle[i] = 1;
  FOR(i, N) {
    if (E[i] != 2)
      iscycle[uf[i]] = 0;
  }

  vector<ll> shortc, O;
  ll Tin = 0, Tout = 0;

  FOR(i, N) if (uf[i] == i) {
    if (uf.count(i) != SB[i])
      iscycle[i] = 0;
    // long cycle
    // cout<<"!"<<i<<" "<<uf.count(i)<<" "<<SB[i]<<" "<<iscycle[i]<<"
    // "<<SC[i]<<endl;
    if (iscycle[i]) {
      if (SB[i] == 1) {
        if (SC[i] > 1)
          shortc.push_back(SC[i] - 1);
      } else {
        X++;
        Tin += SC[i];
      }
    }
  }

  FOR(i, M) {
    if (iscycle[uf[A[i]]] == 0) {
      // cout<<"!add"<<i<<" "<<A[i]<<" "<<B[i]<<" "<<C[i]<<endl;
      if (A[i] != B[i])
        Tout += C[i] - 1;
      else if (C[i] > 1)
        O.push_back(C[i] - 1);
    }
  }

  sort(ALL(shortc));
  sort(ALL(O));
  reverse(ALL(shortc));
  reverse(ALL(O));

  shortc.insert(shortc.begin(), 0);
  O.insert(O.begin(), 0);
  for (i = 1; i < shortc.size(); i++)
    shortc[i] += shortc[i - 1];
  for (i = 1; i < O.size(); i++)
    O[i] += O[i - 1];

  int mi = 1 << 30;
  int z;
  /*
  cout<<P<<" "<<X<<" "<<Tout<<" "<<Tin<<endl;
  FORR(s,shortc) cout<<s<<" ";
  cout<<endl;
  FORR(s,O) cout<<s<<" ";
  cout<<endl;
  */
  FOR(y, shortc.size())
  FOR(z, O.size()) if ((X + y == 0 || Tout + O[z] > 0) &&
                       Tout + Tin + shortc[y] + O[z] >= X) {
    mi = min(mi, P + X + 2 * y + z);
  }

  if (mi == 1 << 30)
    mi = -1;
  cout << mi << endl;
}

int main(int argc, char **argv) {
  string s;
  int i;
  if (argc == 1)
    ios::sync_with_stdio(false), cin.tie(0);
  FOR(i, argc - 1) s += argv[i + 1], s += '\\n';
  FOR(i, s.size()) ungetc(s[s.size() - 1 - i], stdin);
  cout.tie(0);
  solve();
  return 0;
}


Error: 0

Fixed submission:

#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x, to) for (x = 0; x < (to); x++)
#define FORR(x, arr) for (auto &x : arr)
#define ITR(x, c) for (__typeof(c.begin()) x = c.begin(); x != c.end(); x++)
#define ALL(a) (a.begin()), (a.end())
#define ZERO(a) memset(a, 0, sizeof(a))
#define MINUS(a) memset(a, 0xff, sizeof(a))
//-------------------------------------------------------

int N, M;
int A[101010], B[101010], C[101010], E[101010];

int SB[101010];
ll SC[101010];
int iscycle[101010];

template <int um> class UF {
public:
  vector<int> par, rank, cnt;
  UF() {
    par = rank = vector<int>(um, 0);
    cnt = vector<int>(um, 1);
    for (int i = 0; i < um; i++)
      par[i] = i;
  }
  void reinit() {
    int i;
    FOR(i, um) rank[i] = 0, cnt[i] = 1, par[i] = i;
  }
  int operator[](int x) {
    return (par[x] == x) ? (x) : (par[x] = operator[](par[x]));
  }
  int count(int x) { return cnt[operator[](x)]; }
  int operator()(int x, int y) {
    if ((x = operator[](x)) == (y = operator[](y)))
      return x;
    cnt[y] = cnt[x] = cnt[x] + cnt[y];
    if (rank[x] > rank[y])
      return par[x] = y;
    rank[x] += rank[x] == rank[y];
    return par[y] = x;
  }
};
UF<101010> uf;

void solve() {
  int i, j, k, l, r, x, y;
  string s;

  cin >> N >> M;
  ll P = 0, X = 0, Y, Z;
  FOR(i, M) {
    cin >> A[i] >> B[i] >> C[i];
    A[i]--;
    B[i]--;
    E[A[i]]++;
    E[B[i]]++;
    if (uf[A[i]] != uf[B[i]]) {
      SB[uf[A[i]]] = SB[uf[B[i]]] = SB[uf[A[i]]] + SB[uf[B[i]]];
      SC[uf[A[i]]] = SC[uf[B[i]]] = SC[uf[A[i]]] + SC[uf[B[i]]];
      uf(A[i], B[i]);
    }
    if (A[i] != B[i])
      P++;
    SB[uf[A[i]]]++;
    SC[uf[A[i]]] += C[i] - 1;
  }

  FOR(i, N) iscycle[i] = 1;
  FOR(i, N) {
    if (E[i] != 2)
      iscycle[uf[i]] = 0;
  }

  vector<ll> shortc, O;
  ll Tin = 0, Tout = 0;

  FOR(i, N) if (uf[i] == i) {
    if (uf.count(i) != SB[i])
      iscycle[i] = 0;
    // long cycle
    // cout<<"!"<<i<<" "<<uf.count(i)<<" "<<SB[i]<<" "<<iscycle[i]<<endl;
    if (iscycle[i]) {
      if (SB[i] == 1)
        shortc.push_back(SC[i]);
      else {
        X++;
        Tin += SC[i];
      }
    }
  }

  FOR(i, M) {
    if (iscycle[uf[A[i]]] == 0) {
      if (A[i] != B[i])
        Tout += C[i] - 1;
      else
        O.push_back(C[i] - 1);
    }
  }

  if (X == 0) {
    cout << P << endl;
    return;
  }
  if (Tout == 0) {
    cout << -1 << endl;
    return;
  }
  Tout += Tin;

  P += X;
  X -= min(X, Tout);

  assert(X == 0);
  cout << P << endl;
  return;

  sort(ALL(shortc));
  sort(ALL(O));
  reverse(ALL(shortc));
  cout << P << " " << X << " " << Tout << endl;
  FORR(s, shortc) cout << s << " ";
  cout << endl;
  FORR(s, O) cout << s << " ";
  cout << endl;
}

int main(int argc, char **argv) {
  string s;
  int i;
  if (argc == 1)
    ios::sync_with_stdio(false), cin.tie(0);
  FOR(i, argc - 1) s += argv[i + 1], s += '\\n';
  FOR(i, s.size()) ungetc(s[s.size() - 1 - i], stdin);
  cout.tie(0);
  solve();
  return 0;
}