結果

問題 No.1323 うしらずSwap
ユーザー 沙耶花沙耶花
提出日時 2020-12-20 00:53:57
言語 C++17
(gcc 13.2.0 + boost 1.83.0)
結果
AC  
実行時間 1,405 ms / 3,000 ms
コード長 7,279 bytes
コンパイル時間 3,186 ms
コンパイル使用メモリ 226,784 KB
実行使用メモリ 318,060 KB
最終ジャッジ日時 2023-08-09 13:51:12
合計ジャッジ時間 28,064 ms
ジャッジサーバーID
（参考情報） 		judge14 / judge12
このコードへのチャレンジ（β）

テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 2 ms
4,380 KB
testcase_01 AC 2 ms
4,388 KB
testcase_02 AC 1 ms
4,380 KB
testcase_03 AC 1 ms
4,384 KB
testcase_04 AC 2 ms
4,384 KB
testcase_05 AC 2 ms
4,384 KB
testcase_06 AC 2 ms
4,384 KB
testcase_07 AC 1 ms
4,380 KB
testcase_08 AC 2 ms
4,380 KB
testcase_09 AC 1 ms
4,380 KB
testcase_10 AC 2 ms
4,384 KB
testcase_11 AC 1 ms
4,384 KB
testcase_12 AC 2 ms
4,380 KB
testcase_13 AC 2 ms
4,380 KB
testcase_14 AC 1 ms
4,380 KB
testcase_15 AC 1 ms
4,384 KB
testcase_16 AC 639 ms
317,572 KB
testcase_17 AC 1,247 ms
317,332 KB
testcase_18 AC 638 ms
317,836 KB
testcase_19 AC 1,405 ms
317,500 KB
testcase_20 AC 639 ms
317,604 KB
testcase_21 AC 641 ms
317,592 KB
testcase_22 AC 1,298 ms
317,968 KB
testcase_23 AC 668 ms
317,124 KB
testcase_24 AC 1,401 ms
317,640 KB
testcase_25 AC 644 ms
317,056 KB
testcase_26 AC 611 ms
318,060 KB
testcase_27 AC 625 ms
317,716 KB
testcase_28 AC 777 ms
317,444 KB
testcase_29 AC 530 ms
318,060 KB
testcase_30 AC 559 ms
317,524 KB
testcase_31 AC 531 ms
317,120 KB
testcase_32 AC 565 ms
317,440 KB
testcase_33 AC 211 ms
19,508 KB
testcase_34 AC 192 ms
19,440 KB
testcase_35 AC 187 ms
19,572 KB
testcase_36 AC 180 ms
19,696 KB
testcase_37 AC 182 ms
19,920 KB
testcase_38 AC 170 ms
19,504 KB
testcase_39 AC 166 ms
19,496 KB
testcase_40 AC 183 ms
19,520 KB
testcase_41 AC 190 ms
19,828 KB
testcase_42 AC 161 ms
19,456 KB
testcase_43 AC 330 ms
223,516 KB
testcase_44 AC 392 ms
237,652 KB
testcase_45 AC 595 ms
265,352 KB
testcase_46 AC 589 ms
237,932 KB
testcase_47 AC 447 ms
238,304 KB
testcase_48 AC 402 ms
223,676 KB
testcase_49 AC 556 ms
237,908 KB
testcase_50 AC 363 ms
211,604 KB
testcase_51 AC 143 ms
161,500 KB
testcase_52 AC 248 ms
187,496 KB
testcase_53 AC 565 ms
238,188 KB
testcase_54 AC 253 ms
187,756 KB
testcase_55 AC 601 ms
238,056 KB
testcase_56 AC 192 ms
175,884 KB
testcase_57 AC 727 ms
265,244 KB
testcase_58 AC 3 ms
4,380 KB
testcase_59 AC 4 ms
4,380 KB
testcase_60 AC 3 ms
4,384 KB
testcase_61 AC 2 ms
4,384 KB
権限があれば一括ダウンロードができます

ソースコード

diff # 

#include <stdio.h>
#include <bits/stdc++.h>

#include <algorithm>
#include <cassert>
#include <limits>
#include <queue>
#include <vector>

namespace atcoder {

template <class Cap, class Cost> struct mcf_graph {
  public:
    mcf_graph() {}
    mcf_graph(int n) : _n(n), g(n) {}

    int add_edge(int from, int to, Cap cap, Cost cost) {
        assert(0 <= from && from < _n);
        assert(0 <= to && to < _n);
        int m = int(pos.size());
        pos.push_back({from, int(g[from].size())});
        g[from].push_back(_edge{to, int(g[to].size()), cap, cost});
        g[to].push_back(_edge{from, int(g[from].size()) - 1, 0, -cost});
        return m;
    }

    struct edge {
        int from, to;
        Cap cap, flow;
        Cost cost;
    };

    edge get_edge(int i) {
        int m = int(pos.size());
        assert(0 <= i && i < m);
        auto _e = g[pos[i].first][pos[i].second];
        auto _re = g[_e.to][_e.rev];
        return edge{
            pos[i].first, _e.to, _e.cap + _re.cap, _re.cap, _e.cost,
        };
    }
    std::vector<edge> edges() {
        int m = int(pos.size());
        std::vector<edge> result(m);
        for (int i = 0; i < m; i++) {
            result[i] = get_edge(i);
        }
        return result;
    }

    std::pair<Cap, Cost> flow(int s, int t) {
        return flow(s, t, std::numeric_limits<Cap>::max());
    }
    std::pair<Cap, Cost> flow(int s, int t, Cap flow_limit) {
        return slope(s, t, flow_limit).back();
    }
    std::vector<std::pair<Cap, Cost>> slope(int s, int t) {
        return slope(s, t, std::numeric_limits<Cap>::max());
    }
    std::vector<std::pair<Cap, Cost>> slope(int s, int t, Cap flow_limit) {
        assert(0 <= s && s < _n);
        assert(0 <= t && t < _n);
        assert(s != t);
        // variants (C = maxcost):
        // -(n-1)C <= dual[s] <= dual[i] <= dual[t] = 0
        // reduced cost (= e.cost + dual[e.from] - dual[e.to]) >= 0 for all edge
        std::vector<Cost> dual(_n, 0), dist(_n);
        std::vector<int> pv(_n), pe(_n);
        std::vector<bool> vis(_n);
        auto dual_ref = [&]() {
            std::fill(dist.begin(), dist.end(),
                      std::numeric_limits<Cost>::max());
            std::fill(pv.begin(), pv.end(), -1);
            std::fill(pe.begin(), pe.end(), -1);
            std::fill(vis.begin(), vis.end(), false);
            struct Q {
                Cost key;
                int to;
                bool operator<(Q r) const { return key > r.key; }
            };
            std::priority_queue<Q> que;
            dist[s] = 0;
            que.push(Q{0, s});
            while (!que.empty()) {
                int v = que.top().to;
                que.pop();
                if (vis[v]) continue;
                vis[v] = true;
                if (v == t) break;
                // dist[v] = shortest(s, v) + dual[s] - dual[v]
                // dist[v] >= 0 (all reduced cost are positive)
                // dist[v] <= (n-1)C
                for (int i = 0; i < int(g[v].size()); i++) {
                    auto e = g[v][i];
                    if (vis[e.to] || !e.cap) continue;
                    // |-dual[e.to] + dual[v]| <= (n-1)C
                    // cost <= C - -(n-1)C + 0 = nC
                    Cost cost = e.cost - dual[e.to] + dual[v];
                    if (dist[e.to] - dist[v] > cost) {
                        dist[e.to] = dist[v] + cost;
                        pv[e.to] = v;
                        pe[e.to] = i;
                        que.push(Q{dist[e.to], e.to});
                    }
                }
            }
            if (!vis[t]) {
                return false;
            }

            for (int v = 0; v < _n; v++) {
                if (!vis[v]) continue;
                // dual[v] = dual[v] - dist[t] + dist[v]
                //         = dual[v] - (shortest(s, t) + dual[s] - dual[t]) + (shortest(s, v) + dual[s] - dual[v])
                //         = - shortest(s, t) + dual[t] + shortest(s, v)
                //         = shortest(s, v) - shortest(s, t) >= 0 - (n-1)C
                dual[v] -= dist[t] - dist[v];
            }
            return true;
        };
        Cap flow = 0;
        Cost cost = 0, prev_cost = -1;
        std::vector<std::pair<Cap, Cost>> result;
        result.push_back({flow, cost});
        while (flow < flow_limit) {
            if (!dual_ref()) break;
            Cap c = flow_limit - flow;
            for (int v = t; v != s; v = pv[v]) {
                c = std::min(c, g[pv[v]][pe[v]].cap);
            }
            for (int v = t; v != s; v = pv[v]) {
                auto& e = g[pv[v]][pe[v]];
                e.cap -= c;
                g[v][e.rev].cap += c;
            }
            Cost d = -dual[s];
            flow += c;
            cost += c * d;
            if (prev_cost == d) {
                result.pop_back();
            }
            result.push_back({flow, cost});
            prev_cost = cost;
        }
        return result;
    }

  private:
    int _n;

    struct _edge {
        int to, rev;
        Cap cap;
        Cost cost;
    };

    std::vector<std::pair<int, int>> pos;
    std::vector<std::vector<_edge>> g;
};

}  // namespace atcoder

using namespace atcoder;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000000

int H,W;
vector<string> S;
vector<int> dy = {0,0,1,-1},dx = {1,-1,0,0};
vector<vector<int>> get(int r,int c){
	queue<pair<int,int>> Q;
	vector<vector<int>> dis(H,vector<int>(W,Inf));
	dis[r][c] = 0;
	Q.emplace(r,c);
	
	
	while(Q.size()>0){
		int y = Q.front().first,x = Q.front().second;
		Q.pop();
		
		rep(i,4){
			int yy = y+dy[i],xx = x+dx[i];
			if(yy<0||yy>=H||xx<0||xx>=W)continue;
			if(S[yy][xx]=='#')continue;
			if(dis[yy][xx]!=Inf)continue;
			dis[yy][xx] = dis[y][x]+1;
			Q.emplace(yy,xx);
		}
	}
	
	return dis;
}

int main(){
	
	cin>>H>>W;
	S.resize(H);
	int r0,c0,r1,c1;
	cin>>r0>>c0>>r1>>c1;
	r0--,c0--,r1--,c1--;
	rep(i,H){
		cin>>S[i];
	}
	
	auto d0 = get(r0,c0),d1 = get(r1,c1);
	
	if(d0[r1][c1]==Inf)cout<<-1<<endl;
	else{
		int D = d0[r1][c1];
		int cnt = 0;
		rep(i,H){
			rep(j,W){
				if(d0[i][j] + d1[i][j]==D)cnt++;
			}
		}
		int ans = Inf;
		if(cnt>D+1){
			cout<<2*D<<endl;
			return 0;
		}
		else{
			rep(i,H){
				rep(j,W){
					if(d0[i][j]==Inf)continue;
					if(d0[i][j]+d1[i][j]==D)continue;
					rep(k,4){
						int ii = i+dy[k],jj = j+dx[k];
						if(d0[ii][jj]+d1[ii][jj]==D && d0[ii][jj]!=0 && d1[ii][jj]!=0){
							ans = 2*D+2;
						}
					}
					
				}
			}
		}
		
		mcf_graph<int,int> G(2*H*W);
		rep(i,H){
			rep(j,W){
				if(S[i][j]=='#')continue;
				G.add_edge(2*(i*W+j),2*(i*W+j)+1,1,0);
				rep(k,4){
					int ii = i,jj = j;
					ii += dy[k],jj += dx[k];
					if(S[ii][jj]=='#')continue;
					
					G.add_edge(2*(i*W+j)+1,2*(ii*W+jj),1,1);
				}
			}
		}

		auto ret = G.flow(2*(r0*W+c0)+1,2*(r1*W+c1),2);
		if(ret.first>=2)ans = min(ans,ret.second);
		
		rep(i,H){
			rep(j,W){
				if(d0[i][j]==Inf)continue;
				int c = 0;
				rep(k,4){
					int ii = i+dy[k],jj = j+dx[k];
					if(S[ii][jj]=='.')c++;
				}
				if(c>=3){
					ans = min(ans,2*D + 4 + min(d0[i][j],d1[i][j])*4);
				}
			}
		}
		
		if(ans!=Inf)cout<<ans<<endl;
		else{
			
			
			cout<<-1<<endl;
		}
		
	}
	
    return 0;
}
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