hdu 4069 福州赛区网络赛I DLC ***

再遇到一个DLC就刷个专题

#include <stdio.h>
#include <string.h>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <math.h>
#include <stdlib.h>
#include <time.h>
using namespace std;
const int N = 9; //3*3数独
const int MaxN = N*N*N + 10;
const int MaxM = N*N*4 + 10;
const int maxnode = MaxN*4 + MaxM + 10;
char g[MaxN];
int cnt;
struct DLX
{
    int n,m,size;
    int U[maxnode],D[maxnode],R[maxnode],L[maxnode],Row[maxnode],Col[maxnode];
    int H[MaxN],S[MaxM];
    int ansd,ans[MaxN];
    void init(int _n,int _m)
    {
        n = _n;
        m = _m;
        for(int i = 0;i <= m;i++)
        {
            S[i] = 0;
            U[i] = D[i] = i;
            L[i] = i-1;
            R[i] = i+1;
        }
        R[m] = 0; L[0] = m;
        size = m;
        for(int i = 1;i <= n;i++)H[i] = -1;
    }
    void Link(int r,int c)
    {
        ++S[Col[++size]=c];
        Row[size] = r;
        D[size] = D[c];
        U[D[c]] = size;
        U[size] = c;
        D[c] = size;
        if(H[r] < 0)H[r] = L[size] = R[size] = size;
        else
        {
            R[size] = R[H[r]];
            L[R[H[r]]] = size;
            L[size] = H[r];
            R[H[r]] = size;
        }
    }
    void remove(int c)
    {
        L[R[c]] = L[c]; R[L[c]] = R[c];
        for(int i = D[c];i != c;i = D[i])
            for(int j = R[i];j != i;j = R[j])
            {
                U[D[j]] = U[j];
                D[U[j]] = D[j];
                --S[Col[j]];
            }
    }
    void resume(int c)
    {
        for(int i = U[c];i != c;i = U[i])
            for(int j = L[i];j != i;j = L[j])
                ++S[Col[U[D[j]]=D[U[j]]=j]];
        L[R[c]] = R[L[c]] = c;
    }
    void Dance(int d)
    {
        if(cnt > 1)return;
        if(R[0] == 0)
        {
            for(int i = 0;i < d;i++)g[(ans[i]-1)/9] = (ans[i]-1)%9 + '1';
            cnt++;
            return;
        }
        int c = R[0];
        for(int i = R[0];i != 0;i = R[i])
            if(S[i] < S[c])
                c = i;
        remove(c);
        for(int i = D[c];i != c;i = D[i])
        {
            ans[d] = Row[i];
            for(int j = R[i];j != i;j = R[j])remove(Col[j]);
            Dance(d+1);
            if(cnt > 1)return;
            for(int j = L[i];j != i;j = L[j])resume(Col[j]);
        }
        resume(c);
    }
};

int id[20][20];
int a[20][20];
void bfs(int sx,int sy,int d)
{
    queue<pair<int,int> >q;
    q.push(make_pair(sx,sy));
    id[sx][sy] = d;
    while(!q.empty())
    {
        pair<int,int> tmp = q.front();
        int x = tmp.first;
        int y = tmp.second;
        q.pop();
        if(x > 0 && ((a[x][y]%32)/16) == 0)
            if(id[x-1][y] == -1)
            {
                id[x-1][y] = d;
                q.push(make_pair(x-1,y));
            }
        if(x < N-1 && ((a[x][y]%128)/64) == 0)
            if(id[x+1][y] == -1)
            {
                id[x+1][y] = d;
                q.push(make_pair(x+1,y));
            }
        if(y > 0 && ((a[x][y])/128) == 0)
            if(id[x][y-1] == -1)
            {
                id[x][y-1] = d;
                q.push(make_pair(x,y-1));
            }
        if(y < N-1 && ((a[x][y]%64)/32) == 0)
            if(id[x][y+1] == -1)
            {
                id[x][y+1] = d;
                q.push(make_pair(x,y+1));
            }
    }
}
DLX dlx;

int main()
{
    //freopen("in.txt","r",stdin);
    //freopen("out.txt","w",stdout);
    int T;
    scanf("%d",&T);
    int iCase = 0;
    while(T--)
    {
        iCase++;
        for(int i = 0;i < N;i++)
            for(int j = 0;j < N;j++)
                scanf("%d",&a[i][j]);
        memset(id,-1,sizeof(id));
        int index = 0;
        for(int i = 0;i < N;i++)
            for(int j = 0;j < N;j++)
                if(id[i][j] == -1)
                    bfs(i,j,++index);
        dlx.init(N*N*N,N*N*4);
        for(int i = 0;i < N;i++)
            for(int j = 0;j < N;j++)
                for(int k = 1;k <= N;k++)
                {
                    if(a[i][j]%16 != 0 && a[i][j]%16 != k)continue;
                    int r = (i*N+j)*N + k;
                    int c1 = i*N+j+1;
                    int c2 = N*N+i*N+k;
                    int c3 = N*N*2+j*N+k;
                    int c4 = N*N*3+(id[i][j]-1)*N+k;
                    dlx.Link(r,c1);
                    dlx.Link(r,c2);
                    dlx.Link(r,c3);
                    dlx.Link(r,c4);
                }
        cnt = 0;
        dlx.Dance(0);
        printf("Case %d:
",iCase);
        if(cnt == 0)printf("No solution
");
        else if(cnt > 1)printf("Multiple Solutions
");
        else
        {
            for(int i = 0;i < N*N;i++)
            {
                printf("%c",g[i]);
                if(i % N == N - 1)
                    printf("
");
            }
        }
    }
    return 0;
}