codeforces -676D(Theseus and labyrinth)

 1 #include <iostream>
 2 #include <algorithm>
 3 #include <cstring>
 4 #include <cstdio>
 5 #include <bitset>
 6 #include <vector>
 7 #include <queue>
 8 #include <stack>
 9 #include <cmath>
10 #include <list>
11 #include <set>
12 #include <map>
13 #define rep(i,a,b) for(int i = a;i <= b;++ i)
14 #define per(i,a,b) for(int i = a;i >= b;-- i)
15 #define mem(a,b) memset((a),(b),sizeof((a)))
16 #define FIN freopen("in.txt","r",stdin)
17 #define FOUT freopen("out.txt","w",stdout)
18 #define IO ios_base::sync_with_stdio(0),cin.tie(0)
19 #define mid ((l+r)>>1)
20 #define ls (id<<1)
21 #define rs ((id<<1)|1)
22 #define INF 0x3f3f3f3f
23 using namespace std;
24 typedef long long LL;
25 typedef pair<int, int> PIR;
26 const int N = 1e3+5;
27 
28 int n, m, xs, ys, xe, ye, G[N][N], dir[4][2] = {0,-1,1,0,0,1,-1,0};
29 bool vis[N][N][10];
30 string s;
31 struct Node{
32     int x, y, cnt, turn;
33     Node (int _x, int _y, int _cnt, int _turn){
34         x = _x; y = _y; cnt = _cnt; turn = _turn;
35     }
36 };
37 inline int get(char c){
38     if(c == ‘+‘)    return 15;
39     if(c == ‘-‘)    return 5;
40     if(c == ‘|‘)    return 10;
41     if(c == ‘^‘)    return 8;
42     if(c == ‘>‘)    return 4;
43     if(c == ‘<‘)    return 1;
44     if(c == ‘v‘)    return 2;
45     if(c == ‘L‘)    return 14;
46     if(c == ‘R‘)    return 11;
47     if(c == ‘U‘)    return 7;
48     if(c == ‘D‘)    return 13;
49     if(c == ‘*‘)    return 0;
50 }
51 bool judge(int x, int y, int stu){
52     if(x < 1 || x > n || y < 1 || y > m || vis[x][y][stu] || !G[x][y])    return false;
53     return true;
54 }
55 void bfs(){
56     queue <Node> Q;
57     mem(vis, false);
58     Q.push(Node(xs, ys, 0, 0));
59     vis[xs][ys][0] = true;
60     while(!Q.empty()){
61         Node h = Q.front();
62         Q.pop();
63 
64         int xx = h.x, yy = h.y, cntt = h.cnt, turnn = h.turn;
65         if(xx == xe && yy == ye){
66             cout << cntt << endl;
67             return ;
68         }
69         if(!vis[xx][yy][(turnn+1)%4]){
70             Q.push(Node(xx, yy, cntt+1, (turnn+1)%4));
71             vis[xx][yy][(turnn+1)%4] = true;
72         } 
73         rep(i, 0, 3){
74             int xi = xx+dir[i][0], yi = yy+dir[i][1];
75             if(judge(xi, yi, turnn) && (G[xx][yy]&(1<<(i+turnn)%4)) && (G[xi][yi]&(1<<(i+turnn+2)%4))){
76                 Q.push(Node(xi, yi, cntt+1, turnn));
77                 vis[xi][yi][turnn] = true;
78             }
79         }
80     }
81     cout << -1 << endl;
82     return ;
83 }
84 int main()
85 {IO;
86     cin >> n >> m;
87     rep(i, 1, n){
88         cin >> s;
89         rep(j, 0, m-1)    G[i][j+1] = get(s[j]);
90     }
91     cin >> xs >> ys;
92     cin >> xe >> ye;
93     bfs();
94     return 0;
95 }