Submission #66137078

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Source Code Expand

#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(n);i++)
#include"atcoder/all"
using namespace atcoder;
typedef modint998244353 mi;
using namespace std;
#define all(a) a.begin(),a.end()
#define compress(a) sort(all(a));a.erase(unique(all(a)),a.end())
typedef long long ll;
typedef pair<ll,ll> P;
constexpr ll mod=998244353;
constexpr ll inf=3e18;
template <class T>
struct Matrix {
  vector<vector<T> > A;

  Matrix() {}

  Matrix(size_t n, size_t m) : A(n, vector<T>(m, 0)) {}

  Matrix(size_t n) : A(n, vector<T>(n, 0)) {};

  size_t size() const {
    if (A.empty()) return 0;
    assert(A.size() == A[0].size());
    return A.size();
  }

  size_t height() const { return (A.size()); }

  size_t width() const { return (A[0].size()); }

  inline const vector<T> &operator[](int k) const { return (A.at(k)); }

  inline vector<T> &operator[](int k) { return (A.at(k)); }

  static Matrix I(size_t n) {
    Matrix mat(n);
    for (int i = 0; i < n; i++) mat[i][i] = 1;
    return (mat);
  }

  Matrix &operator+=(const Matrix &B) {
    size_t n = height(), m = width();
    assert(n == B.height() && m == B.width());
    for (int i = 0; i < n; i++)
      for (int j = 0; j < m; j++) (*this)[i][j] += B[i][j];
    return (*this);
  }

  Matrix &operator-=(const Matrix &B) {
    size_t n = height(), m = width();
    assert(n == B.height() && m == B.width());
    for (int i = 0; i < n; i++)
      for (int j = 0; j < m; j++) (*this)[i][j] -= B[i][j];
    return (*this);
  }

  Matrix &operator*=(const Matrix &B) {
    size_t n = height(), m = B.width(), p = width();
    assert(p == B.height());
    vector<vector<T> > C(n, vector<T>(m, 0));
    for (int i = 0; i < n; i++)
      for (int j = 0; j < m; j++)
        for (int k = 0; k < p; k++)
          C[i][j] = (C[i][j] + (*this)[i][k] * B[k][j]);
    A.swap(C);
    return (*this);
  }

  Matrix &operator^=(long long k) {
    Matrix B = Matrix::I(height());
    while (k > 0) {
      if (k & 1) B *= *this;
      *this *= *this;
      k >>= 1LL;
    }
    A.swap(B.A);
    return (*this);
  }

  Matrix operator+(const Matrix &B) const { return (Matrix(*this) += B); }

  Matrix operator-(const Matrix &B) const { return (Matrix(*this) -= B); }

  Matrix operator*(const Matrix &B) const { return (Matrix(*this) *= B); }

  Matrix operator^(const long long k) const { return (Matrix(*this) ^= k); }

  friend ostream &operator<<(ostream &os, Matrix &p) {
    size_t n = p.height(), m = p.width();
    for (int i = 0; i < n; i++) {
      os << "[";
      for (int j = 0; j < m; j++) {
        os << p[i][j] << (j + 1 == m ? "]\n" : ",");
      }
    }
    return (os);
  }

  T determinant() {
    Matrix B(*this);
    assert(width() == height());
    T ret = 1;
    for (int i = 0; i < width(); i++) {
      int idx = -1;
      for (int j = i; j < width(); j++) {
        if (B[j][i] != 0) idx = j;
      }
      if (idx == -1) return (0);
      if (i != idx) {
        ret *= -1;
        swap(B[i], B[idx]);
      }
      ret *= B[i][i];
      T vv = B[i][i];
      for (int j = 0; j < width(); j++) {
        B[i][j] /= vv;
      }
      for (int j = i + 1; j < width(); j++) {
        T a = B[j][i];
        for (int k = 0; k < width(); k++) {
          B[j][k] -= B[i][k] * a;
        }
      }
    }
    return (ret);
  }
};

template <typename T>
pair<T, vector<int> > hungarian(Matrix<T> &A) {
  const T infty = numeric_limits<T>::max();
  const int N = (int)A.height();
  const int M = (int)A.width();
  vector<int> P(M), way(M);
  vector<T> U(N, 0), V(M, 0), minV;
  vector<bool> used;

  for (int i = 1; i < N; i++) {
    P[0] = i;
    minV.assign(M, infty);
    used.assign(M, false);
    int j0 = 0;
    while (P[j0] != 0) {
      int i0 = P[j0], j1 = 0;
      used[j0] = true;
      T delta = infty;
      for (int j = 1; j < M; j++) {
        if (used[j]) continue;
        T curr = A[i0][j] - U[i0] - V[j];
        if (curr < minV[j]) minV[j] = curr, way[j] = j0;
        if (minV[j] < delta) delta = minV[j], j1 = j;
      }
      for (int j = 0; j < M; j++) {
        if (used[j])
          U[P[j]] += delta, V[j] -= delta;
        else
          minV[j] -= delta;
      }
      j0 = j1;
    }
    do {
      P[j0] = P[way[j0]];
      j0 = way[j0];
    } while (j0 != 0);
  }
  return {-V[0], P};
}

int main(){
	int h,w;
	cin>>h>>w;
	vector<vector<ll>>A(h,vector<ll>(w));
	ll sum=0;
	rep(i,h){
		rep(j,w){
			cin>>A[i][j];
			sum+=A[i][j];
		}
	}

	Matrix<ll> mat((h*w+1)/2+1);
	rep(i,h){
		rep(j,w){
			if(j+1<w){
				int v1=(i*w+j),v2=i*w+j+1;

				if(A[i][j]+A[i][j+1]<0){
					if((i+j)%2==0){
						mat[v1/2+1][v2/2+1]=A[i][j]+A[i][j+1];
					}
					else mat[v2/2+1][v1/2+1]=A[i][j]+A[i][j+1];
				}
			}
			if(i+1<h){
				int v1=(i*w+j),v2=i*w+j+w;
				if(A[i][j]+A[i+1][j]<0){
					if((i+j)%2==0){
						mat[v1/2+1][v2/2+1]=A[i][j]+A[i+1][j];
					}
					else mat[v2/2+1][v1/2+1]=A[i][j]+A[i+1][j];
				}
			}
		}
	}

	cout<<sum-hungarian(mat).first<<endl;
}

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