【HDU】4210 Sudominoku

#include<cstdio>
#include<cstring>
#include<algorithm>
#define MAXN 300000
#define MAXL 1010
#define MAXM 10
#define INF 0x7FFFFFFF
using namespace std;
int L[MAXN], R[MAXN], U[MAXN], D[MAXN];
int S[MAXL], H[MAXL], C[MAXN], X[MAXN], Q[MAXL];
bool vis[MAXM][MAXM], G[MAXM][MAXM], has[MAXL];
int size, row, a[MAXM][MAXM];
int go[4][2] = { 0, 1, 0, -1, 1, 0, -1, 0 };
void Init(int n, int m) {
    int i;
    memset(vis, false, sizeof(vis));
    memset(has, false, sizeof(has));
    memset(a, 0, sizeof(a));
    memset(G, false, sizeof(G));
    for (i = 0; i <= n; i++)
        H[i] = -1;
    for (i = 0; i <= m; i++) {
        L[i + 1] = i;
        R[i] = i + 1;
        U[i] = D[i] = i;
        S[i] = 0;
    }
    R[m] = 0;
    size = m + 1;
}
void Link(int r, int c) {
    U[size] = c;
    D[size] = D[c];
    U[D[c]] = size;
    D[c] = size;
    if (H[r] < 0)
        H[r] = L[size] = R[size] = size;
    else {
        L[size] = H[r];
        R[size] = R[H[r]];
        L[R[H[r]]] = size;
        R[H[r]] = size;
    }
    S[c]++;
    X[size] = r;
    C[size++] = c;
}
void Remove(int c) {
    int i, j;
    L[R[c]] = L[c];
    R[L[c]] = R[c];
    for (i = D[c]; i != c; i = D[i]) {
        for (j = R[i]; j != i; j = R[j]) {
            U[D[j]] = U[j];
            D[U[j]] = D[j];
            S[C[j]]--;
        }
    }
}
void Resume(int c) {
    int i, j;
    L[R[c]] = R[L[c]] = c;
    for (i = D[c]; i != c; i = D[i]) {
        for (j = R[i]; j != i; j = R[j]) {
            U[D[j]] = D[U[j]] = j;
            S[C[j]]++;
        }
    }
}
bool DFS(int now) {
    if (now > 81)
        return true;
    int x, y, nx, ny, i;
    x = (now - 1) / 9 + 1;
    y = now - (x - 1) * 9;
    if (vis[x][y])
        return DFS(now + 1);
    vis[x][y] = true;
    for (i = 0; i < 4; i++) {
        nx = x + go[i][0];
        ny = y + go[i][1];
        if (nx > 0 && nx < 10 && ny > 0 && ny < 10 && !vis[nx][ny]
                && !G[a[x][y]][a[nx][ny]]) {
            vis[nx][ny] = true;
            G[a[x][y]][a[nx][ny]] = G[a[nx][ny]][a[x][y]] = true;
            if (DFS(now + 1))
                return true;
            G[a[x][y]][a[nx][ny]] = G[a[nx][ny]][a[x][y]] = false;
            vis[nx][ny] = false;
        }
    }
    vis[x][y] = false;
    return false;
}
bool Dance() {
    int i, j, k, temp, c;
    if (R[0] == 0) {
        for (i = j = k = 1; i < row; i++) {
            if (has[i]) {
                a[j][k] = Q[i];
                k++;
                if (k > 9) {
                    k = 1;
                    j++;
                }
            }
        }
        if (DFS(1)) {
            for (i = 1; i < 10; i++) {
                for (j = 1; j < 10; j++)
                    printf("%d", a[i][j]);
                putchar('\n');
            }
            return true;
        }
        return false;
    }
    for (temp = INF, i = R[0]; i; i = R[i]) {
        if (temp > S[i]) {
            temp = S[i];
            c = i;
        }
    }
    Remove(c);
    for (i = D[c]; i != c; i = D[i]) {
        has[X[i]] = true;
        for (j = R[i]; j != i; j = R[j])
            Remove(C[j]);
        if (Dance())
            return true;
        for (j = L[i]; j != i; j = L[j])
            Resume(C[j]);
        has[X[i]] = false;
    }
    Resume(c);
    return false;
}
int main() {
    int ca = 1;
    int n, i, j, k, x1, x2;
    char y1, z1, y2, z2;
    while (scanf("%d", &n), n) {
        Init(729, 324);
        for (i = 0; i < n; i++) {
            scanf("%d %c %c %d %c %c", &x1, &y1, &z1, &x2, &y2, &z2);
            y1 -= 'A' - 1;
            z1 -= '0';
            y2 -= 'A' - 1;
            z2 -= '0';
            a[y1][z1] = x1;
            a[y2][z2] = x2;
            vis[y1][z1] = vis[y2][z2] = true;
            G[x1][x2] = G[x2][x1] = true;
        }
        for (i = 1; i < 10; i++) {
            scanf(" %c %c", &y1, &y2);
            y1 -= 'A' - 1;
            y2 -= '0';
            a[y1][y2] = i;
            vis[y1][y2] = true;
        }
        for (row = i = 1; i < 10; i++) {
            for (j = 1; j < 10; j++) {
                if (a[i][j]) {
                    k = a[i][j];
                    Q[row] = k;
                    Link(row, (i - 1) * 9 + k);
                    Link(row, 81 + (j - 1) * 9 + k);
                    Link(row, 162 + ((i - 1) / 3 * 3 + (j - 1) / 3) * 9 + k);
                    Link(row, 243 + (i - 1) * 9 + j);
                    row++;
                } else {
                    for (k = 1; k < 10; k++) {
                        Q[row] = k;
                        Link(row, (i - 1) * 9 + k);
                        Link(row, 81 + (j - 1) * 9 + k);
                        Link(row,
                                162 + ((i - 1) / 3 * 3 + (j - 1) / 3) * 9 + k);
                        Link(row, 243 + (i - 1) * 9 + j);
                        row++;
                    }
                }
            }
        }
        printf("Puzzle %d\n", ca++);
        Dance();
    }
    return 0;
}