ural 1250. Sea Burial

  1 /**
  2 Create By yzx - stupidboy
  3 */
  4 #include <cstdio>
  5 #include <cstring>
  6 #include <cstdlib>
  7 #include <cmath>
  8 #include <deque>
  9 #include <vector>
 10 #include <queue>
 11 #include <iostream>
 12 #include <algorithm>
 13 #include <map>
 14 #include <set>
 15 #include <ctime>
 16 #include <iomanip>
 17 using namespace std;
 18 typedef long long LL;
 19 typedef double DB;
 20 #define MIT (2147483647)
 21 #define INF (1000000001)
 22 #define MLL (1000000000000000001LL)
 23 #define sz(x) ((int) (x).size())
 24 #define clr(x, y) memset(x, y, sizeof(x))
 25 #define puf push_front
 26 #define pub push_back
 27 #define pof pop_front
 28 #define pob pop_back
 29 #define ft first
 30 #define sd second
 31 #define mk make_pair
 32 
 33 inline int Getint()
 34 {
 35     int Ret = 0;
 36     char Ch = ‘ ‘;
 37     bool Flag = 0;
 38     while(!(Ch >= ‘0‘ && Ch <= ‘9‘))
 39     {
 40         if(Ch == ‘-‘) Flag ^= 1;
 41         Ch = getchar();
 42     }
 43     while(Ch >= ‘0‘ && Ch <= ‘9‘)
 44     {
 45         Ret = Ret * 10 + Ch - ‘0‘;
 46         Ch = getchar();
 47     }
 48     return Flag ? -Ret : Ret;
 49 }
 50 
 51 const int N = 510;
 52 const int DX[] = {-1, 0, 1, 0, -1, -1, 1, 1}, DY[] = {0, -1, 0, 1, -1, 1, -1, 1};
 53 #define Land 1
 54 #define Sea 2
 55 int n, m, sx, sy;
 56 int graph[N][N], mark[N][N];
 57 int ans;
 58 
 59 inline void Input()
 60 {
 61     scanf("%d%d%d%d", &n, &m, &sx, &sy);
 62     swap(sx, sy), swap(n, m);
 63     for(int i = 1; i <= n; i++)
 64         for(int j = 1; j <= m; j++)
 65         {
 66             char ch = ‘ ‘;
 67             while(ch != ‘.‘ && ch != ‘#‘) ch = getchar();
 68             graph[i][j] = ch == ‘.‘ ? Sea : Land;
 69         }
 70 }
 71 
 72 inline bool Check(int x, int y, int state)
 73 {
 74     if(x < 1 || x > n || y < 1 || y > m) return 0;
 75     if(!(graph[x][y] & state) || mark[x][y]) return 0;
 76     return 1;
 77 }
 78 
 79 inline void Draw(int sx, int sy, int state, int tag)
 80 {
 81     static int que[N * N][2], tail;
 82     mark[sx][sy] = tag;
 83     tail = 1, que[1][0] = sx, que[1][1] = sy;
 84     for(int head = 1; head <= tail; head++)
 85     {
 86         int ux = que[head][0], uy = que[head][1];
 87         for(int t = 0; t < 8; t++)
 88         {
 89             if(t > 3 && graph[ux][uy] == Land) break;
 90             int vx = ux + DX[t], vy = uy + DY[t];
 91             if(!Check(vx, vy, state)) continue;
 92             mark[vx][vy] = tag, tail++;
 93             que[tail][0] = vx, que[tail][1] = vy;
 94         }
 95     }
 96 }
 97 
 98 inline void Solve()
 99 {
100     if(graph[sx][sy] == ‘#‘)
101     {
102         puts("0");
103         return;
104     }
105     
106     Draw(sx, sy, Sea, 1);
107     for(int i = 1; i <= n; i++)
108     {
109         Draw(i, 0, Land | Sea, 2);
110         Draw(i, m + 1, Land | Sea, 2);
111     }
112     for(int i = 1; i <= m; i++)
113     {
114         Draw(0, i, Land | Sea, 2);
115         Draw(n + 1, i, Land | Sea, 2);
116     }
117     
118     for(int i = 1; i <= n; i++)
119         for(int j = 1; j <= m; j++)
120             if(!mark[i][j] && graph[i][j] == Land)
121             {
122                 ans++;
123                 Draw(i, j, Land, 3);
124             }
125     
126     printf("%d\n", ans);
127 }
128 
129 int main()
130 {
131     freopen("a.in", "r", stdin);
132     Input();
133     Solve();
134     return 0;
135 }