【POJ】3074 Sudoku

  1 #include<cstdio>

  2 #include<cstring>

  3 #define MAXM 10

  4 #define MAXL 324

  5 #define MAXN 240000

  6 #define INF 0x7FFFFFFF

  7 char sd[MAXM][MAXM];

  8 int L[MAXN], R[MAXN], U[MAXN], D[MAXN], H[MAXN];

  9 int size, C[MAXN], S[MAXN], X[MAXN], Q[MAXN], vis[MAXL * 3];

 10 bool Read()

 11 {

 12     int i, j;

 13     for (i = 1; i < MAXM; i++)

 14     {

 15         for (j = 1; j < MAXM; j++)

 16         {

 17             scanf(" %c", &sd[i][j]);

 18             if (sd[i][j] == 'e')

 19                 return false;

 20         }

 21     }

 22     return true;

 23 }

 24 void Init()

 25 {

 26     int i;

 27     for (i = 0; i <= MAXL; i++)

 28     {

 29         L[i + 1] = i;

 30         R[i] = i + 1;

 31         U[i] = D[i] = i;

 32         S[i] = 0;

 33     }

 34     R[MAXL] = 0;

 35     size = MAXL + 1;

 36 }

 37 void Remove(int c)

 38 {

 39     int i, j;

 40     L[R[c]] = L[c];

 41     R[L[c]] = R[c];

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

 43     {

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

 45         {

 46             U[D[j]] = U[j];

 47             D[U[j]] = D[j];

 48             S[C[j]]--;

 49         }

 50     }

 51 }

 52 void Resume(int c)

 53 {

 54     int i, j;

 55     L[R[c]] = c;

 56     R[L[c]] = c;

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

 58     {

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

 60         {

 61             U[D[j]] = j;

 62             D[U[j]] = j;

 63             S[C[j]]++;

 64         }

 65     }

 66 }

 67 inline void Link(int r, int c)

 68 {

 69     D[size] = D[c];

 70     U[size] = c;

 71     U[D[c]] = size;

 72     D[c] = size;

 73     if (H[r] < 0)

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

 75     else

 76     {

 77         L[size] = H[r];

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

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

 80         R[H[r]] = size;

 81     }

 82     S[c]++;

 83     X[size] = r;

 84     C[size++] = c;

 85 }

 86 bool Dance(int now)

 87 {

 88     int i, j, c, temp;

 89     if (R[0] == 0)

 90         return true;

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

 92     {

 93         if (S[i] < temp)

 94         {

 95             temp = S[i];

 96             c = i;

 97         }

 98     }

 99     Remove(c);

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

101     {

102         vis[X[i]] = true;

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

104             Remove(C[j]);

105         if (Dance(now + 1))

106             return true;

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

108             Resume(C[j]);

109         vis[X[i]] = false;

110     }

111     Resume(c);

112     return false;

113 }

114 int main()

115 {

116     int i, j, k, r;

117     while (Read())

118     {

119         Init();

120         for (r = 0, i = 1; i < MAXM; i++)

121         {

122             for (j = 1; j < MAXM; j++)

123             {

124                 if (sd[i][j] == '.')

125                 {

126                     for (k = 1; k < MAXM; k++)

127                     {

128                         H[++r] = -1;

129                         Q[r] = k;

130                         Link(r, (i - 1) * 9 + k);

131                         Link(r, 81 + (j - 1) * 9 + k);

132                         Link(r, 162 + ((i - 1) / 3 * 3 + (j - 1) / 3) * 9 + k);

133                         Link(r, 243 + (i - 1) * 9 + j);

134                     }

135                 }

136                 else

137                 {

138                     H[++r] = -1;

139                     k = sd[i][j] - '0';

140                     Q[r] = k;

141                     Link(r, (i - 1) * 9 + k);

142                     Link(r, 81 + (j - 1) * 9 + k);

143                     Link(r, 162 + ((i - 1) / 3 * 3 + (j - 1) / 3) * 9 + k);

144                     Link(r, 243 + (i - 1) * 9 + j);

145                 }

146             }

147         }

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

149         Dance(0);

150         for (i = 1; i <= r; i++)

151         {

152             if (vis[i])

153                 printf("%d", Q[i]);

154         }

155         putchar('\n');

156     }

157     return 0;

158 }