【HDU】3529 Bomberman - Just Search!

  1 #include<cstdio>

  2 #include<cstring>

  3 #include<algorithm>

  4 #define MAXM 20

  5 #define MAXN 60000

  6 #define MAXL 300

  7 #define INF 0x7FFFFFFF

  8 using namespace std;

  9 char s[MAXM][MAXM];

 10 int L[MAXN], R[MAXN], U[MAXN], D[MAXN];

 11 int H[MAXL], S[MAXL], C[MAXN];

 12 int pos[MAXM][MAXM], ans, size;

 13 bool vis[MAXL];

 14 void Init(int n)

 15 {

 16     int i;

 17     for (i = 0; i <= n; i++)

 18     {

 19         R[i] = i + 1;

 20         L[i + 1] = i;

 21         U[i] = D[i] = i;

 22         S[i] = 0;

 23     }

 24     R[n] = 0;

 25     size = n + 1;

 26 }

 27 void Link(int r, int c)

 28 {

 29     U[size] = c;

 30     D[size] = D[c];

 31     U[D[c]] = size;

 32     D[c] = size;

 33     if (H[r] < 0)

 34         H[r] = L[size] = R[size] = size;

 35     else

 36     {

 37         L[size] = H[r];

 38         R[size] = R[H[r]];

 39         L[R[H[r]]] = size;

 40         R[H[r]] = size;

 41     }

 42     S[c]++;

 43     C[size++] = c;

 44 }

 45 void Remove(int c)

 46 {

 47     int i;

 48     for (i = D[c]; i != c; i = D[i])

 49     {

 50         L[R[i]] = L[i];

 51         R[L[i]] = R[i];

 52     }

 53 }

 54 void Resume(int c)

 55 {

 56     int i;

 57     for (i = D[c]; i != c; i = D[i])

 58         L[R[i]] = R[L[i]] = i;

 59 }

 60 int A()

 61 {

 62     int i, j, k, res;

 63     memset(vis, false, sizeof(vis));

 64     for (res = 0, i = R[0]; i; i = R[i])

 65     {

 66         if (!vis[i])

 67         {

 68             res++;

 69             for (j = D[i]; j != i; j = D[j])

 70             {

 71                 for (k = R[j]; k != j; k = R[k])

 72                     vis[C[k]] = true;

 73             }

 74         }

 75     }

 76     return res;

 77 }

 78 void Dance(int now)

 79 {

 80     if (R[0] == 0)

 81         ans = min(ans, now);

 82     else if (now + A() < ans)

 83     {

 84         int i, j, temp, c;

 85         for (temp = INF,i = R[0]; i; i = R[i])

 86         {

 87             if (temp > S[i])

 88             {

 89                 temp = S[i];

 90                 c = i;

 91             }

 92         }

 93         for (i = D[c]; i != c; i = D[i])

 94         {

 95             Remove(i);

 96             for (j = R[i]; j != i; j = R[j])

 97                 Remove(j);

 98             Dance(now + 1);

 99             for (j = L[i]; j != i; j = L[j])

100                 Resume(j);

101             Resume(i);

102         }

103     }

104 }

105 int main()

106 {

107     int n, m, i, j, k, r;

108     while (~scanf("%d%d", &n, &m))

109     {

110         memset(pos, 0, sizeof(pos));

111         for (i = k = 0; i < n; i++)

112         {

113             for (j = 0; j < m; j++)

114             {

115                 scanf(" %c", &s[i][j]);

116                 if (s[i][j] == '#')

117                 {

118                     k++;

119                     pos[i][j] = k;

120                 }

121             }

122         }

123         Init(k);

124         for (i = r = 0; i < n; i++)

125         {

126             for (j = 0; j < m; j++)

127             {

128                 H[++r] = -1;

129                 if (s[i][j] == '.')

130                 {

131                     for (k = j + 1; k < m && s[i][k] == '.'; k++)

132                         ;

133                     if (s[i][k] == '#')

134                         Link(r, pos[i][k]);

135                     for (k = j - 1; k >= 0 && s[i][k] == '.'; k--)

136                         ;

137                     if (s[i][k] == '#')

138                         Link(r, pos[i][k]);

139                     for (k = i + 1; k < n && s[k][j] == '.'; k++)

140                         ;

141                     if (s[k][j] == '#')

142                         Link(r, pos[k][j]);

143                     for (k = i - 1; k >= 0 && s[k][j] == '.'; k--)

144                         ;

145                     if (s[k][j] == '#')

146                         Link(r, pos[k][j]);

147                 }

148             }

149         }

150         ans = INF;

151         Dance(0);

152         printf("%d\n", ans);

153     }

154     return 0;

155 }