【FOJ】2076 SUDOKU

#include<cstdio>
#include<cstring>
#include<set>
#define MAXN 9
#define MAXM 500000
#define INF 0x7FFFFFFF
using namespace std;
char sd[MAXN][MAXN];
int L[MAXM], R[MAXM], U[MAXM], D[MAXM];
int H[MAXM], S[MAXM], C[MAXM], pos[MAXN << 3][MAXN << 3];
int size, cnt;
void Init(int m)
{
    int i;
    for (i = 0; i <= m; i++)
    {
        R[i] = i + 1;
        L[i + 1] = i;
        U[i] = D[i] = i;
        S[i] = 0;
    }
    R[m] = 0;
    size = m + 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]] = 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]]++;
        }
    }
}
inline 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]++;
    C[size++] = c;
}
void Dance()
{
    if (R[0] == 0)
        cnt++;
    else
    {
        int i, j, temp, c;
        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])
        {
            for (j = R[i]; j != i; j = R[j])
                Remove(C[j]);
            Dance();
            for (j = L[i]; j != i; j = L[j])
                Resume(C[j]);
        }
        Resume(c);
    }
}
void Build()
{
    set<int> myset;
    int i, j, k, r, t;
    for (i = r = 0; i < MAXN; i++)
    {
        for (j = 0; j < MAXN; j++)
        {
            if (sd[i][j] == '0')
            {
                for (k = 1; k <= MAXN; k++)
                {
                    H[++r] = -1;
                    Link(r, i * 9 + k);
                    Link(r, 81 + j * 9 + k);
                    Link(r, 162 + (i / 3 * 3 + j / 3) * 9 + k);
                    Link(r, 243 + i * 9 + j + 1);
                }
            }
            else if (sd[i][j] >= '1' && sd[i][j] <= '9')
            {
                k = sd[i][j] - '0';
                H[++r] = -1;
                Link(r, i * 9 + k);
                Link(r, 81 + j * 9 + k);
                Link(r, 162 + (i / 3 * 3 + j / 3) * 9 + k);
                Link(r, 243 + i * 9 + j + 1);
            }
        }
    }
    for (i = 0; i < 26; i++)
    {
        for (j = 0; j < MAXN; j++)
        {
            pos[i][j] = ++r;
            H[r] = -1;
        }
    }
    for (i = 0; i < MAXN; i++)
    {
        for (j = 0; j < MAXN; j++)
        {
            if (sd[i][j] >= 'a' && sd[i][j] <= 'z')
            {
                t = sd[i][j] - 'a';
                for (k = 1; k <= MAXN; k++)
                {
                    Link(pos[t][k - 1], i * 9 + k);
                    Link(pos[t][k - 1], 81 + j * 9 + k);
                    Link(pos[t][k - 1], 162 + (i / 3 * 3 + j / 3) * 9 + k);
                    Link(pos[t][k - 1], 243 + i * 9 + j + 1);
                    if (!myset.count(t * 26 + k - 1))
                    {
                        Link(pos[t][k - 1], 324 + k);
                        myset.insert(t * 26 + k - 1);
                    }
                }
            }
        }
    }
    for (i = 1; i <= MAXN; i++)
    {
        H[++r] = -1;
        Link(r, 324 + i);
    }
}
inline int Get(char ch)
{
    if (ch >= '0' && ch <= '9')
        return ch - '0';
    return ch - 'a' + 10;
}
bool OK()
{
    int i, j, k;
    bool x[MAXN << 3], letter[MAXN << 3], y[MAXN][MAXN << 3];
    memset(letter, false, sizeof(letter));
    memset(y, false, sizeof(y));
    for (i = 0; i < MAXN; i++)
    {
        memset(x, false, sizeof(x));
        for (j = 0; j < MAXN; j++)
        {
            k = Get(sd[i][j]);
            if (k && y[i / 3 * 3 + j / 3][k])
                return false;
            y[i / 3 * 3 + j / 3][k] = true;
            if (k > 9)
                letter[k] = true;
            if (k && x[k])
                return false;
            x[k] = true;
        }
    }
    for (i = k = 0; i < MAXN << 3; i++)
    {
        if (letter[i])
            k++;
    }
    if (k > 9)
        return false;
    for (j = 0; j < MAXN; j++)
    {
        memset(x, false, sizeof(x));
        for (i = 0; i < MAXN; i++)
        {
            k = Get(sd[i][j]);
            if (k && x[k])
                return false;
            x[k] = true;
        }
    }
    return true;
}
int main()
{
    int c, i, j;
    scanf("%d", &c);
    while (c--)
    {
        Init(333);
        for (i = cnt = 0; i < MAXN; i++)
        {
            for (j = 0; j < MAXN; j++)
                scanf(" %c", &sd[i][j]);
        }
        if (OK())
        {
            Build();
            Dance();
        }
        printf("%d\n", cnt);
    }
    return 0;
}