【HDOJ】4210 Su-domino-ku

DLX。在模板的基础上增加一个FILL属性，略修改即可。

/* 4210 */
#include <iostream>
#include <string>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <vector>
#include <deque>
#include <algorithm>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <climits>
#include <cctype>
#include <cassert>
#include <functional>
#include <iterator>
#include <iomanip>
using namespace std;
//#pragma comment(linker,"/STACK:102400000,1024000")

#define sti                set<int>
#define stpii            set<pair<int, int> >
#define mpii            map<int,int>
#define vi                vector<int>
#define pii                pair<int,int>
#define vpii            vector<pair<int,int> >
#define rep(i, a, n)     for (int i=a;i<n;++i)
#define per(i, a, n)     for (int i=n-1;i>=a;--i)
#define clr                clear
#define pb                 push_back
#define mp                 make_pair
#define fir                first
#define sec                second
#define all(x)             (x).begin(),(x).end()
#define SZ(x)             ((int)(x).size())
#define lson            l, mid, rt<<1
#define rson            mid+1, r, rt<<1|1

typedef struct {
    static const int maxc = 5*9*9+5;
    static const int maxr = 13205;
    static const int maxn = maxr * maxc;
    
    int n, sz;
    int S[maxc];
    
    int row[maxn], col[maxn];
    int L[maxn], R[maxn], U[maxn], D[maxn];
    
    int ansd, ans[maxr];
    
    void init(int n_) {
        n = n_;
        
        rep(i, 0, n+1) {
            L[i] = i - 1;
            R[i] = i + 1;
            U[i] = i;
            D[i] = i;
            col[i] = i;
        }
        
        L[0] = n;
        R[n] = 0;
        
        sz = n + 1;
        memset(S, 0, sizeof(S));
    }
    
    void addRow(int r, vi columns) {
        int size = SZ(columns);
        int first = sz;
        
        rep(i, 0, size) {
            int c = columns[i];
            
            L[sz] = sz - 1;
            R[sz] = sz + 1;
            
            D[sz] = c;
            U[sz] = U[c];
            D[U[c]] = sz;
            U[c] = sz;
            
            row[sz] = r;
            col[sz] = c;
            
            ++S[c];
            ++sz;
        }
        
        R[sz-1] = first;
        L[first] = sz-1;
    }
    
    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 restore(int c) {
        L[R[c]] = c;
        R[L[c]] = c;
        for (int i=D[c]; i!=c; i=D[i]) {
            for (int j=R[i]; j!=i; j=R[j]) {
                U[D[j]] = j;
                D[U[j]] = j;
                ++S[col[j]];
            }
        }
    }
    
    bool dfs(int d) {
        if (R[0] == 0) {
            ansd = d;
            return true;
        }
        
        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]);
            }
            if(dfs(d + 1))    return true;
            for (int j=L[i]; j!=i; j=L[j]) {
                restore(col[j]);
            }
        }
        restore(c);
        
        return false; 
    }
    
    void solve(vi& v) {
        v.clr();
        
        dfs(0);
        
        rep(i, 0, ansd)
            v.pb(ans[i]);
    }
    
} DLX;

typedef struct {
    int a, b;
    int r, c;
    int d;
} node_t;

const int SLOT = 0;
const int ROW = 1;
const int COL = 2;
const int SUB = 3;
const int FILL = 4;
const int maxn = 13205;
int M[10][10];
bool mark[10][10];
DLX solver;
node_t nd[maxn];
int rn;
vi ans;

int encode(int a, int b, int c) {
    return a*81 + b*9 + c+1;
}

void decode(int code, int& a, int& b, int& c) {
    --code;
    c = code % 9;
    code /= 9;
    b = code % 9;
    code /= 9;
    a = code;
}

void init() {
    rn = 1;
    memset(mark, false, sizeof(mark));
}

void input(int n) {
    int r, c;
    int x1, x2;
    char ps1[5], ps2[5], ps[5];
    
    solver.init(5*9*9);
    init();
    rep(i, 0, n) {
        scanf("%d %s %d %s", &x1, ps1, &x2, ps2);
        vi columns;
        
        // handle 1-st
        r = ps1[0]-'A';
        c = ps1[1]-'1';
        --x1;
        columns.pb(encode(SLOT, r, c));
        columns.pb(encode(ROW, r, x1));
        columns.pb(encode(COL, c, x1));
        columns.pb(encode(SUB, r/3*3+c/3, x1));
        M[r][c] = x1;
        
        // handle 2-nd
        r = ps2[0]-'A';
        c = ps2[1]-'1';
        --x2;
        columns.pb(encode(SLOT, r, c));
        columns.pb(encode(ROW, r, x2));
        columns.pb(encode(COL, c, x2));
        columns.pb(encode(SUB, r/3*3+c/3, x2));
        M[r][c] = x2;
        
        mark[x1][x2] = mark[x2][x1] = true;
        columns.pb(encode(FILL, x1, x2));
        columns.pb(encode(FILL, x2, x1));
        solver.addRow(rn++, columns);
    }
    rep(i, 0, 9) {
        scanf("%s", ps);
        r = ps[0]-'A';
        c = ps[1]-'1';
        M[r][c] = i;
        mark[i][i] = true;
        vi columns;
        columns.pb(encode(SLOT, r, c));
        columns.pb(encode(ROW, r, i));
        columns.pb(encode(COL, c, i));
        columns.pb(encode(SUB, r/3*3+c/3, i));
        columns.pb(encode(FILL, i, i));
        solver.addRow(rn++, columns);
    }
    rep(i, 0, 9) {
        rep(j, 0, 9) {
            if (mark[i][j])
                continue;
            for (r=0; r<=8; ++r) {
                for (c=0; c<8; ++c) {
                    nd[rn].a = i;
                    nd[rn].b = j;
                    nd[rn].d = 0;
                    nd[rn].r = r;
                    nd[rn].c = c;
                    
                    vi columns;
                    columns.pb(encode(SLOT, r, c));
                    columns.pb(encode(ROW, r, i));
                    columns.pb(encode(COL, c, i));
                    columns.pb(encode(SUB, r/3*3+c/3, i));
                    int cc = c + 1;
                    columns.pb(encode(SLOT, r, cc));
                    columns.pb(encode(ROW, r, j));
                    columns.pb(encode(COL, cc, j));
                    columns.pb(encode(SUB, r/3*3+cc/3, j));
                    columns.pb(encode(FILL, i, j));
                    columns.pb(encode(FILL, j, i));
                    solver.addRow(rn++, columns);
                }
            }
            
            for(r=0; r<8; ++r) {
                int rr = r + 1;
                for (c=0; c<=8; ++c) {
                    nd[rn].a = i;
                    nd[rn].b = j;
                    nd[rn].d = 1;
                    nd[rn].r = r;
                    nd[rn].c = c;
                    
                    vi columns;
                    columns.pb(encode(SLOT, r, c));
                    columns.pb(encode(ROW, r, i));
                    columns.pb(encode(COL, c, i));
                    columns.pb(encode(SUB, r/3*3+c/3, i));
                    columns.pb(encode(SLOT, rr, c));
                    columns.pb(encode(ROW, rr, j));
                    columns.pb(encode(COL, c, j));
                    columns.pb(encode(SUB, rr/3*3+c/3, j));
                    columns.pb(encode(FILL, i, j));
                    columns.pb(encode(FILL, j, i));
                    solver.addRow(rn++, columns);
                }
            }
        }
    }
}

void solve(int n) {
    solver.solve(ans);
    int sz = SZ(ans), id;
    n += 9;
    
    rep(i, 0, sz) {
        if (ans[i] > n) {
            id = ans[i];
            if (nd[id].d) {
                M[nd[id].r][nd[id].c] = nd[id].a;
                M[nd[id].r+1][nd[id].c] = nd[id].b;
            } else {
                M[nd[id].r][nd[id].c] = nd[id].a;
                M[nd[id].r][nd[id].c+1] = nd[id].b;
            }
        }
    }
    
    rep(i, 0, 9) {
        rep(j, 0, 9) {
            ++M[i][j];
            printf("%d", M[i][j]);
        }
        putchar('
');
    }
}

int main() {
    ios::sync_with_stdio(false);
    #ifndef ONLINE_JUDGE
        freopen("data.in", "r", stdin);
        freopen("data.out", "w", stdout);
    #endif
    
    int n;
    int t = 0;
    
    while (scanf("%d",&n)!=EOF && n) {
        memset(mark, false, sizeof(mark));
        input(n);
        printf("Puzzle %d
", ++t);
        solve(n);
    }
    
    #ifndef ONLINE_JUDGE
        printf("time = %d.
", (int)clock());
    #endif
    
    return 0;
}