【HDU】4069 Squiggly Sudoku

#include<cstdio>
#include<cstring>
#define MAXN 9
#define MAXH 800
#define MAXL 324
#define MAXM 240000
#define INF 0x7FFFFFFF
int size, cnt, a[MAXN][MAXN], sd[MAXN][MAXN], belong[MAXN][MAXN];
int L[MAXM], R[MAXM], U[MAXM], D[MAXM], C[MAXM], X[MAXM];
int S[MAXH], H[MAXH], Q[MAXH], ans[MAXL];
bool vis[MAXH];
void Dir(int x, int y, bool &up, bool &right, bool &down, bool &left)
{
    sd[x][y] = a[x][y];
    up = right = down = left = false;
    if (sd[x][y] >= 128)
    {
        sd[x][y] -= 128;
        left = true;
    }
    if (sd[x][y] >= 64)
    {
        sd[x][y] -= 64;
        down = true;
    }
    if (sd[x][y] >= 32)
    {
        sd[x][y] -= 32;
        right = true;
    }
    if (sd[x][y] >= 16)
    {
        sd[x][y] -= 16;
        up = true;
    }

}
void DFS(int x, int y, int color)
{
    bool up, right, down, left;
    belong[x][y] = color;
    Dir(x, y, up, right, down, left);
    if (!up && !belong[x - 1][y])
        DFS(x - 1, y, color);
    if (!down && !belong[x + 1][y])
        DFS(x + 1, y, color);
    if (!right && !belong[x][y + 1])
        DFS(x, y + 1, color);
    if (!left && !belong[x][y - 1])
        DFS(x, y - 1, color);
}
void Init()
{
    int i;
    for (i = 0; i <= MAXL; i++)
    {
        L[i + 1] = i;
        R[i] = i + 1;
        U[i] = D[i] = i;
        S[i] = 0;
    }
    R[MAXL] = 0;
    size = MAXL + 1;
}
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]] = 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]] = j;
            D[U[j]] = j;
            S[C[j]]++;
        }
    }
}
inline void Link(int r, int c)
{
    D[size] = D[c];
    U[size] = 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;
}
bool Dance(int r)
{
    int i, j, temp, c;
    if (R[0] == 0)
    {
        if (!cnt)
        {
            for (i = j = 1; i <= r; i++)
            {
                if (vis[i])
                    ans[j++] = Q[i];
            }
        }
        cnt++;
        return cnt > 1;
    }
    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])
    {
        vis[X[i]] = true;
        for (j = R[i]; j != i; j = R[j])
            Remove(C[j]);
        if (Dance(r))
            return true;
        for (j = L[i]; j != i; j = L[j])
            Resume(C[j]);
        vis[X[i]] = false;
    }
    Resume(c);
    return false;
}
int main()
{
    int c, i, j, k, r, ca = 1;
    scanf("%d", &c);
    while (c--)
    {
        memset(belong, 0, sizeof(belong));
        for (i = 0; i < MAXN; i++)
        {
            for (j = 0; j < MAXN; j++)
                scanf("%d", &a[i][j]);
        }
        for (i = k = 0; i < MAXN; i++)
        {
            for (j = 0; j < MAXN; j++)
            {
                if (!belong[i][j])
                    DFS(i, j, ++k);
            }
        }
        Init();
        for (i = r = 0; i < MAXN; i++)
        {
            for (j = 0; j < MAXN; j++)
            {
                if (sd[i][j])
                {
                    k = sd[i][j];
                    H[++r] = -1;
                    Q[r] = k;
                    Link(r, i * 9 + k);
                    Link(r, 81 + j * 9 + k);
                    Link(r, 162 + (belong[i][j] - 1) * 9 + k);
                    Link(r, 243 + i * 9 + j + 1);
                }
                else
                {
                    for (k = 1; k <= MAXN; k++)
                    {
                        H[++r] = -1;
                        Q[r] = k;
                        Link(r, i * 9 + k);
                        Link(r, 81 + j * 9 + k);
                        Link(r, 162 + (belong[i][j] - 1) * 9 + k);
                        Link(r, 243 + i * 9 + j + 1);
                    }
                }
            }
        }
        cnt = 0;
        memset(vis, false, sizeof(vis));
        Dance(r);
        printf("Case %d:\n", ca++);
        if (cnt == 0)
            puts("No solution");
        else if (cnt > 1)
            puts("Multiple Solutions");
        else
        {
            for (i = 1; i <= 81; i++)
            {
                printf("%d", ans[i]);
                if (i % 9 == 0)
                    putchar('\n');
            }
        }
    }
    return 0;
}