【UVa】387 A Puzzling Problem

  1 #include<cstdio>

  2 #include<cstring>

  3 #define MAXM 10

  4 #define MAXN 100000

  5 #define MAXL 110

  6 #define INF 0x7FFFFFFF

  7 struct node {

  8     int h, l;

  9     char s[MAXM][MAXM];

 10 };

 11 struct answer {

 12     int pos, h, l;

 13 };

 14 answer ans[MAXL];

 15 node sq[MAXM];

 16 bool vis[MAXL];

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

 18 int H[MAXN], S[MAXN], C[MAXN], X[MAXN];

 19 int size;

 20 char a[MAXM][MAXM];

 21 void Init(int m) {

 22     int i;

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

 24     for (i = 0; i <= m; i++) {

 25         L[i + 1] = i;

 26         R[i] = i + 1;

 27         U[i] = D[i] = i;

 28         S[i] = 0;

 29     }

 30     R[m] = 0;

 31     size = m + 1;

 32 }

 33 void Link(int r, int c) {

 34     U[size] = c;

 35     D[size] = D[c];

 36     U[D[c]] = size;

 37     D[c] = size;

 38     if (H[r] < 0)

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

 40     else {

 41         L[size] = H[r];

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

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

 44         R[H[r]] = size;

 45     }

 46     S[c]++;

 47     X[size] = r;

 48     C[size++] = c;

 49 }

 50 void Remove(int c) {

 51     int i, j;

 52     L[R[c]] = L[c];

 53     R[L[c]] = R[c];

 54     for (i = D[c]; i != c; i = D[i]) {

 55         for (j = R[i]; j != i; j = R[j]) {

 56             U[D[j]] = U[j];

 57             D[U[j]] = D[j];

 58             S[C[j]]--;

 59         }

 60     }

 61 }

 62 void Resume(int c) {

 63     int i, j;

 64     L[R[c]] = R[L[c]] = c;

 65     for (i = D[c]; i != c; i = D[i]) {

 66         for (j = R[i]; j != i; j = R[j]) {

 67             U[D[j]] = D[U[j]] = j;

 68             S[C[j]]++;

 69         }

 70     }

 71 }

 72 bool Dance() {

 73     if (R[0] == 0)

 74         return true;

 75     int i, j, temp, c;

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

 77         if (temp > S[i]) {

 78             temp = S[i];

 79             c = i;

 80         }

 81     }

 82     Remove(c);

 83     for (i = D[c]; i != c; i = D[i]) {

 84         vis[X[i]] = true;

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

 86             Remove(C[j]);

 87         if (Dance())

 88             return true;

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

 90             Resume(C[j]);

 91         vis[X[i]] = false;

 92     }

 93     Resume(c);

 94     return false;

 95 }

 96 void Build(int n) {

 97     int i, j, k, t, p, r;

 98     for (i = r = 0; i < n; i++) {

 99         for (j = 0; j <= 4 - sq[i].h; j++) {

100             for (k = 0; k <= 4 - sq[i].l; k++) {

101                 H[++r] = -1;

102                 Link(r, 16 + i + 1);

103                 ans[r].pos = i;

104                 ans[r].h = j;

105                 ans[r].l = k;

106                 for (t = 0; t < sq[i].h; t++) {

107                     for (p = 0; p < sq[i].l; p++) {

108                         if (sq[i].s[t][p] != '0')

109                             Link(r, 4 * (j + t) + k + p + 1);

110                     }

111                 }

112             }

113         }

114     }

115 }

116 int main() {

117     int n, i, j, k;

118     bool flag = true;

119     while (scanf("%d", &n), n) {

120         if (flag)

121             flag = false;

122         else

123             putchar('\n');

124         Init(16 + n);

125         for (i = 0; i < n; i++) {

126             scanf("%d%d", &sq[i].h, &sq[i].l);

127             for (j = 0; j < sq[i].h; j++) {

128                 for (k = 0; k < sq[i].l; k++)

129                     scanf(" %c", &sq[i].s[j][k]);

130             }

131         }

132         Build(n);

133         if (Dance()) {

134             for (i = 1; i < MAXL; i++) {

135                 if (vis[i]) {

136                     for (j = 0; j < sq[ans[i].pos].h; j++) {

137                         for (k = 0; k < sq[ans[i].pos].l; k++) {

138                             if (sq[ans[i].pos].s[j][k] != '0')

139                                 a[j + ans[i].h][k + ans[i].l] = '1'

140                                         + ans[i].pos;

141                         }

142                     }

143                 }

144             }

145             for (i = 0; i < 4; i++) {

146                 for (j = 0; j < 4; j++)

147                     putchar(a[i][j]);

148                 putchar('\n');

149             }

150         } else

151             puts("No solution possible");

152     }

153     return 0;

154 }