#include using namespace std; using lint = long long int; using pint = pair; using plint = pair; struct fast_ios { fast_ios(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_; #define ALL(x) (x).begin(), (x).end() #define SZ(x) ((lint)(x).size()) #define POW2(n) (1LL << (n)) #define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i=i##_begin_;i--) #define REP(i, n) FOR(i,0,n) #define IREP(i, n) IFOR(i,0,n) template void ndarray(vector &vec, int len) { vec.resize(len); } template void ndarray(vector &vec, int len, Args... args) { vec.resize(len); for (auto &v : vec) ndarray(v, args...); } template bool mmax(T &m, const T q) { if (m < q) {m = q; return true;} else return false; } template bool mmin(T &m, const T q) { if (m > q) {m = q; return true;} else return false; } template pair operator+(const pair &l, const pair &r) { return make_pair(l.first + r.first, l.second + r.second); } template pair operator-(const pair &l, const pair &r) { return make_pair(l.first - r.first, l.second - r.second); } template istream &operator>>(istream &is, vector &vec){ for (auto &v : vec) is >> v; return is; } ///// This part below is only for debug, not used ///// template ostream &operator<<(ostream &os, const vector &vec){ os << "["; for (auto v : vec) os << v << ","; os << "]"; return os; } template ostream &operator<<(ostream &os, const deque &vec){ os << "deq["; for (auto v : vec) os << v << ","; os << "]"; return os; } template ostream &operator<<(ostream &os, const set &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const unordered_set &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const multiset &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const unordered_multiset &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const pair &pa){ os << "(" << pa.first << "," << pa.second << ")"; return os; } template ostream &operator<<(ostream &os, const map &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const unordered_map &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; } #define dbg(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ") " << __FILE__ << endl; ///// END ///// /* #include #include #include using namespace __gnu_pbds; // find_by_order(), order_of_key() template using pbds_set = tree, rb_tree_tag, tree_order_statistics_node_update>; template using pbds_map = tree, rb_tree_tag, tree_order_statistics_node_update>; */ struct UndirectedGraph { using Pint = pair; using Plint = pair; int V; int E; int dDefault; vector weights; vector> to; vector edges; UndirectedGraph(int V, lint dDefault=-1) : V(V), E(0), dDefault(dDefault), to(vector>(V)) {} void add_edge(int v1, int v2, lint w) { to[v1].push_back(Pint(v2, E)); // to[v2].push_back(Pint(v1, E)); edges.push_back(Pint(v1, v2)); weights.push_back(w); E++; } vector dist; void dijkstra(int start) { dist = vector(V, dDefault); priority_queue, greater> pq; pq.push(Plint(0, start)); while (!pq.empty()) { Plint p = pq.top(); pq.pop(); int v = p.second; if (dist[v] >= 0 && dist[v] < p.first) continue; dist[v] = p.first; // cout << "dist[" << v << "] = " << p.first << endl; for (auto vnxt : to[v]) { lint dnxt = dist[v] + weights[vnxt.second]; if (dnxt < dist[vnxt.first] || dist[vnxt.first] < 0) { dist[vnxt.first] = dnxt; pq.push(Plint(dnxt, vnxt.first)); } } } } }; int main() { int H, W; cin >> H >> W; vector A(H); cin >> A; UndirectedGraph g(H * W); vector dx{0, 0, 1, -1}; vector dy{1, -1, 0, 0}; REP(i, H) REP(j, W) { REP(d, 4) { int in = i + dx[d]; int jn = j + dy[d]; if (in < 0 or jn < 0 or in >= H or jn >= W) continue; lint D = 1; if (A[in][jn] != '.') D += in + jn; g.add_edge(i * W + j, in * W + jn, D); } } g.dijkstra(0); cout << g.dist.back() << endl; }