【POJ】3076 Sudoku

/* 3076 */
#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 DLX {
static const int maxc = 4*16*16 + 5;
static const int maxr = 16*16*16 + 5;
static const int maxnode = 16*16*16*4 + 5;
int n, sz;
int S[maxc];

int row[maxnode], col[maxnode];
int L[maxnode], R[maxnode], U[maxnode], D[maxnode];

int ansd, ans[maxr];

void init(int n_)  {
n = n_;

for (int i=0; i<=n; ++i) {
L[i] = i - 1;
R[i] = i + 1;
U[i] = i;
D[i] = i;
}
L[0] = n;
R
= 0;

sz = n + 1;
memset(S, 0, sizeof(S));
}

void addRow(int r, vi columns) {
int first = sz;
int size = SZ(columns);

for (int i=0; i<size; ++i) {
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) {
for (int i=U[c]; i!=c; i=U[i]) {
for (int j=L[i]; j!=i; j=L[j]) {
++S[col[j]];
U[D[j]] = j;
D[U[j]] = j;
}
}
L[R[c]] = c;
R[L[c]] = c;
}

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;
}

bool solve(vector<int>& v) {
v.clr();

if (!dfs(0))    return false;

for (int i=0; i<ansd; ++i)
v.pb(ans[i]);

return true;
}
} DLX;

DLX solver;
const int SLOT = 0;
const int ROW = 1;
const int COL = 2;
const int SUB = 3;

int encode(int a, int b, int c) {
return a*256+b*16+c+1;
}

void decode(int code, int& a, int& b, int& c) {
--code;
c = code%16;
code /= 16;
b = code%16;
code /= 16;
a = code;
}

char puzzle[16][20];

bool read() {
rep(i, 0, 16)
if (scanf("%s", puzzle[i])!=1)
return false;
return true;
}

int main() {
ios::sync_with_stdio(false);
#ifndef ONLINE_JUDGE
freopen("data.in", "r", stdin);
freopen("data.out", "w", stdout);
#endif

int kase = 0;

while (read()) {
if (kase++)
putchar('\n');

solver.init(1024);
rep(r, 0, 16) {
rep(c, 0, 16) {
rep(v, 0, 16) {
if (puzzle[r][c]=='-' || puzzle[r][c]=='A'+v) {
vi columns;
columns.pb(encode(SLOT, r, c));
columns.pb(encode(ROW, r, v));
columns.pb(encode(COL, c, v));
columns.pb(encode(SUB, r/4*4+c/4, v));
solver.addRow(encode(r, c, v), columns);
}
}
}
}

vi ans;
bool flag = solver.solve(ans);
#ifndef ONLINE_JUDGE
puts(flag ? "Yes":"No");
#endif
int sz = SZ(ans);

rep(i, 0, sz) {
int r, c, v;
decode(ans[i], r, c, v);
puzzle[r][c] = v + 'A';
}

rep(i, 0, 16)
puts(puzzle[i]);
}

#ifndef ONLINE_JUDGE
printf("time = %d.\n", (int)clock());
#endif

return 0;
}