Problem p01736 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep1(i, n) for (int i = 1; i <= (int)(n); i++)
#define all(c) c.begin(), c.end()
#define pb push_back
#define fs first
#define sc second
#define show(x) cout << #x << " = " << x << endl
#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)
using namespace std;
template <class T> ostream &operator<<(ostream &o, const vector<T> &vc) {
  o << "sz=" << vc.size() << endl << "[";
  for (T &v : vc)
    o << v << ",";
  cout << "]" << endl;
  return o;
}
// Z/pZ
typedef int ll;
struct mint {
  const static ll mod = 2;
  ll a;
  mint() : a(0) {}
  mint(ll a) : a((a % mod + mod) % mod) {}
  mint operator+=(const mint &b) {
    if ((a += b.a) >= mod)
      a -= mod;
    return *this;
  }
  mint operator-=(const mint &b) {
    if ((a += mod - b.a) >= mod)
      a -= mod;
    return *this;
  }
  mint operator*=(const mint &b) {
    (a *= b.a) %= mod;
    return *this;
  }
  mint operator+(const mint &b) { return mint(*this) += b; }
  mint operator-(const mint &b) { return mint(*this) -= b; }
  mint operator*(const mint &b) { return mint(*this) *= b; }
  mint operator-() { return mint(-a); }
  int extgcd(int a, int b, int &x, int &y) const {
    int u[] = {a, 1, 0}, v[] = {b, 0, 1};
    while (*v) {
      int t = *u / *v;
      rep(i, 3) swap(u[i] -= t * v[i], v[i]);
    }
    if (u[0] < 0)
      rep(i, 3) u[i] = -u[i];
    x = u[1], y = u[2];
    return u[0];
  }
  mint inv() const {
    int x, y;
    extgcd(a, mod, x, y);
    if (x < 0)
      x += mod;
    return mint(x);
  }
  mint operator/=(const mint &b) {
    (*this) *= b.inv();
    return *this;
  }
  mint operator/(const mint &b) { return mint(*this) /= b; }
  bool operator==(const mint &b) const { return a == b.a; }
  friend ostream &operator<<(ostream &o, const mint &x) { return o << x.a; }
};
const mint zero(0), one(1);
bool iszero(mint x) { return x.a == 0; }
template <class T> struct Matrix {
  int H, W;
  vector<vector<T>> m;
  Matrix() : H(0), W(0) {}
  Matrix(int H, int W)
      : H(H), W(W), m(vector<vector<T>>(H, vector<T>(W, zero))) {}
  //???0*W?????????????????¨?£????????????§??±????????????????????????????????§???????????????
  // Matrix(vector< vector<T> > m):m(m),H(m.size()),W(m[0].size()){}
  static Matrix E(int N) {
    Matrix a(N, N);
    rep(i, N) a.m[i][i] = one;
    return a;
  }
  Matrix operator+=(const Matrix &b) {
    assert(H == b.H && W == b.W);
    rep(i, H) rep(j, H) m[i][j] += b.m[i][j];
    return *this;
  }
  Matrix operator-=(const Matrix &b) {
    assert(H == b.H && W == b.W);
    rep(i, H) rep(j, H) m[i][j] -= b.m[i][j];
    return *this;
  }
  Matrix operator+(const Matrix &b) { return Matrix(*this) += b; }
  Matrix operator-(const Matrix &b) { return Matrix(*this) -= b; }
  Matrix operator*(const Matrix &b) {
    assert(W == b.H);
    Matrix c(H, b.W);
    rep(i, H) rep(k, W) rep(j, b.W) c.m[i][j] += m[i][k] * b.m[k][j];
    return c;
  }
  Matrix operator*=(const Matrix &b) { return (*this) = (*this) * b; }
  vector<T> operator*(const vector<T> &b) {
    assert(W == b.size());
    vector<T> c(H);
    rep(i, H) rep(j, W) c[i] += m[i][j] * b[j];
    return c;
  }
  int sweep(int var = -1) { // return rank ????????¨
    if (var < 0)
      var = W;
    int r = 0;
    vector<bool> used(H);
    rep(j, var) {
      int i = 0;
      while (i < H && (used[i] || iszero(m[i][j])))
        i++;
      if (i == H)
        continue;
      used[i] = true;
      r++;
      T t = m[i][j];
      rep(k, W) m[i][k] = m[i][k] / t;
      rep(k, H) if (k != i) {
        t = m[k][j];
        rep(l, W) m[k][l] = m[k][l] - m[i][l] * t;
      }
      //			show((*this));
    }
    return r;
  }
  Matrix inv() {
    assert(H == W);
    Matrix a(H, 2 * H);
    rep(i, H) rep(j, H) a.m[i][j] = m[i][j];
    rep(i, H) a.m[i][i + H] = one;
    int r = a.sweep(H);
    //		show(r);
    if (r < H)
      return Matrix();
    Matrix b(H, H);
    rep(i_, H) {
      int i = -1;
      rep(j, H) if (a.m[i_][j] == one) i = j;
      assert(i >= 0);
      rep(j, H) b.m[i][j] = a.m[i_][j + H];
    }
    return b;
  }
  pair<int, vector<T>>
  sle(vector<T> b) { // return pair( ?§£????¬????(?????????????????????-1) ,x
                     // s.t.Ax=b)
    assert(H == b.size());
    Matrix a(H, W + 1);
    rep(i, H) rep(j, W) a.m[i][j] = m[i][j];
    rep(i, H) a.m[i][W] = b[i];
    a.sweep(W);
    int d = 0;
    rep(i, H) {
      bool all0 = 1;
      rep(j, W) if (!iszero(a.m[i][j])) all0 = 0;
      if (all0) {
        if (!iszero(a.m[i][W])) {
          return pair<int, vector<T>>(-1, vector<T>());
        }
        d++;
      }
    }
    rep(i_, H) {
      int i = -1;
      rep(j, W) if (a.m[i_][j] == one) i = j;
      if (i < 0)
        continue;
      b[i] = a.m[i_][W];
      //			show(b[i]);
    }
    return pair<int, vector<T>>(d, b);
  }
  friend ostream &operator<<(ostream &o, const Matrix &m) {
    o << m.H << " * " << m.W << endl;
    rep(i, m.H) {
      o << "[";
      rep(j, m.W) o << m.m[i][j] << " ";
      o << "]" << endl;
    }
    return o;
  }
};
template <class T> Matrix<T> ex(Matrix<T> a, int t) {
  int N = a.H;
  Matrix<mint> x = Matrix<mint>::E(N);
  while (t) {
    if (t % 2)
      x *= a;
    a *= a;
    t /= 2;
  }
  return x;
}
int main() {
  int N, T;
  cin >> N;
  Matrix<mint> a(N, N);
  rep(i, N) rep(j, N) {
    int x;
    cin >> x;
    a.m[i][j] = mint(x);
  }
  vector<mint> b(N);
  rep(i, N) {
    int x;
    cin >> x;
    b[i] = mint(x);
  }
  cin >> T;
  a = ex(a, T);
  auto p = a.sle(b);
  //	assert(a*p.sc==b);
  //	show(p.fs);
  //	vector<mint> c=a*p.sc;
  //	assert(c==b);
  //	rep(i,N) assert(c[i]==b[i]);
  if (p.fs == -1) {
    puts("none");
  } else if (p.fs > 0) {
    puts("ambiguous");
  } else {
    rep(i, N) cout << p.sc[i] << (i == N - 1 ? "\\n" : " ");
  }
}

Error: 0

Fixed submission:

#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep1(i, n) for (int i = 1; i <= (int)(n); i++)
#define all(c) c.begin(), c.end()
#define pb push_back
#define fs first
#define sc second
#define show(x) cout << #x << " = " << x << endl
#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)
using namespace std;
template <class T> ostream &operator<<(ostream &o, const vector<T> &vc) {
  o << "sz=" << vc.size() << endl << "[";
  for (T &v : vc)
    o << v << ",";
  cout << "]" << endl;
  return o;
}
// Z/pZ
typedef int ll;
struct mint {
  const static ll mod = 2;
  ll a;
  mint() : a(0) {}
  mint(ll a) : a((a % mod + mod) % mod) {}
  mint operator+=(const mint &b) {
    if ((a += b.a) >= mod)
      a -= mod;
    return *this;
  }
  mint operator-=(const mint &b) {
    if ((a += mod - b.a) >= mod)
      a -= mod;
    return *this;
  }
  mint operator*=(const mint &b) {
    (a *= b.a) %= mod;
    return *this;
  }
  mint operator+(const mint &b) { return mint(*this) += b; }
  mint operator-(const mint &b) { return mint(*this) -= b; }
  mint operator*(const mint &b) { return mint(*this) *= b; }
  mint operator-() { return mint(-a); }
  int extgcd(int a, int b, int &x, int &y) const {
    int u[] = {a, 1, 0}, v[] = {b, 0, 1};
    while (*v) {
      int t = *u / *v;
      rep(i, 3) swap(u[i] -= t * v[i], v[i]);
    }
    if (u[0] < 0)
      rep(i, 3) u[i] = -u[i];
    x = u[1], y = u[2];
    return u[0];
  }
  mint inv() const {
    int x, y;
    extgcd(a, mod, x, y);
    if (x < 0)
      x += mod;
    return mint(x);
  }
  mint operator/=(const mint &b) {
    (*this) *= b.inv();
    return *this;
  }
  mint operator/(const mint &b) { return mint(*this) /= b; }
  bool operator==(const mint &b) const { return a == b.a; }
  friend ostream &operator<<(ostream &o, const mint &x) { return o << x.a; }
};
const mint zero(0), one(1);
bool iszero(mint x) { return x.a == 0; }
template <class T> struct Matrix {
  int H, W;
  vector<vector<T>> m;
  Matrix() : H(0), W(0) {}
  Matrix(int H, int W)
      : H(H), W(W), m(vector<vector<T>>(H, vector<T>(W, zero))) {}
  //???0*W?????????????????¨?£????????????§??±????????????????????????????????§???????????????
  // Matrix(vector< vector<T> > m):m(m),H(m.size()),W(m[0].size()){}
  static Matrix E(int N) {
    Matrix a(N, N);
    rep(i, N) a.m[i][i] = one;
    return a;
  }
  Matrix operator+=(const Matrix &b) {
    assert(H == b.H && W == b.W);
    rep(i, H) rep(j, H) m[i][j] += b.m[i][j];
    return *this;
  }
  Matrix operator-=(const Matrix &b) {
    assert(H == b.H && W == b.W);
    rep(i, H) rep(j, H) m[i][j] -= b.m[i][j];
    return *this;
  }
  Matrix operator+(const Matrix &b) { return Matrix(*this) += b; }
  Matrix operator-(const Matrix &b) { return Matrix(*this) -= b; }
  Matrix operator*(const Matrix &b) {
    assert(W == b.H);
    Matrix c(H, b.W);
    rep(i, H) rep(k, W) rep(j, b.W) c.m[i][j] += m[i][k] * b.m[k][j];
    return c;
  }
  Matrix operator*=(const Matrix &b) { return (*this) = (*this) * b; }
  vector<T> operator*(const vector<T> &b) {
    assert(W == b.size());
    vector<T> c(H);
    rep(i, H) rep(j, W) c[i] += m[i][j] * b[j];
    return c;
  }
  int sweep(int var = -1) { // return rank ????????¨
    if (var < 0)
      var = W;
    int r = 0;
    vector<bool> used(H);
    rep(j, var) {
      int i = 0;
      while (i < H && (used[i] || iszero(m[i][j])))
        i++;
      if (i == H)
        continue;
      used[i] = true;
      r++;
      T t = m[i][j];
      rep(k, W) m[i][k] = m[i][k] / t;
      rep(k, H) if (k != i) {
        t = m[k][j];
        rep(l, W) m[k][l] = m[k][l] - m[i][l] * t;
      }
      //			show((*this));
    }
    return r;
  }
  Matrix inv() {
    assert(H == W);
    Matrix a(H, 2 * H);
    rep(i, H) rep(j, H) a.m[i][j] = m[i][j];
    rep(i, H) a.m[i][i + H] = one;
    int r = a.sweep(H);
    //		show(r);
    if (r < H)
      return Matrix();
    Matrix b(H, H);
    rep(i_, H) {
      int i = -1;
      rep(j, H) if (a.m[i_][j] == one) i = j;
      assert(i >= 0);
      rep(j, H) b.m[i][j] = a.m[i_][j + H];
    }
    return b;
  }
  pair<int, vector<T>>
  sle(vector<T> b) { // return pair( ?§£????¬????(?????????????????????-1) ,x
                     // s.t.Ax=b)
    assert(H == b.size());
    Matrix a(H, W + 1);
    rep(i, H) rep(j, W) a.m[i][j] = m[i][j];
    rep(i, H) a.m[i][W] = b[i];
    a.sweep(W);
    int d = 0;
    rep(i, H) {
      bool all0 = 1;
      rep(j, W) if (!iszero(a.m[i][j])) all0 = 0;
      if (all0) {
        if (!iszero(a.m[i][W])) {
          return pair<int, vector<T>>(-1, vector<T>());
        }
        d++;
      }
    }
    rep(i_, H) {
      int i = -1;
      rep(j, W) if (a.m[i_][j] == one) i = j;
      assert(i >= 0);
      b[i] = a.m[i_][W];
      //			show(b[i]);
    }
    return pair<int, vector<T>>(d, b);
  }
  friend ostream &operator<<(ostream &o, const Matrix &m) {
    o << m.H << " * " << m.W << endl;
    rep(i, m.H) {
      o << "[";
      rep(j, m.W) o << m.m[i][j] << " ";
      o << "]" << endl;
    }
    return o;
  }
};
template <class T> Matrix<T> ex(Matrix<T> a, int t) {
  int N = a.H;
  Matrix<mint> x = Matrix<mint>::E(N);
  while (t) {
    if (t % 2)
      x *= a;
    a *= a;
    t /= 2;
  }
  return x;
}
int main() {
  int N, T;
  cin >> N;
  Matrix<mint> a(N, N);
  rep(i, N) rep(j, N) {
    int x;
    cin >> x;
    a.m[i][j] = mint(x);
  }
  vector<mint> b(N);
  rep(i, N) {
    int x;
    cin >> x;
    b[i] = mint(x);
  }
  cin >> T;
  a = ex(a, T);
  auto p = a.sle(b);
  //	assert(a*p.sc==b);
  //	show(p.fs);
  //	vector<mint> c=a*p.sc;
  //	assert(c==b);
  //	rep(i,N) assert(c[i]==b[i]);
  if (p.fs == -1) {
    puts("none");
  } else if (p.fs > 0) {
    puts("ambiguous");
  } else {
    rep(i, N) cout << p.sc[i] << (i == N - 1 ? "\\n" : " ");
  }
}