DLX to solve Sudoku template Nyoj 722, POJ 2676

Complex Sudoku ratio DFS fast//Space change time #include <stdio.h> #include <string.h> #include <iostream> using namespace std;
#define N 300000 #define INF 0x3fffffff Char g[10][10];
int ans[1000];
int u[5000],d[5000],r[5000],l[5000],num[5000],h[1000],save[5000],save1[5000];
int flag,head;
const int n=729;
const int m=324;

int id;
        void Prepare () {for (int i=0;i<=m;i++) {num[i]=0;
        D[i]=i;
        U[i]=i;
        r[i]=i+1;
    L[i+1]=i;
    } r[m]=0; memset (h,-1,sizeof (H));
    Record the first point in each row} void link (int tn,int tm) {id++; Save1[id]=tn; Record line ++NUM[SAVE[ID]=TM];
    Record column D[ID]=D[TM];
    u[D[tm]]=id;
    U[id]=tm;
    D[tm]=id;
    if (h[tn]<0) H[tn]=l[id]=r[id]=id;
        else {r[id]=r[h[tn]];
        l[R[h[tn]]]=id;
        r[H[tn]]=id;
    L[ID]=H[TN];
    } void Build () {id=m;
    int sum;
    Prepare ();
    int tn=0;
        for (int i=1;i<=81;i++) {for (int j=1;j<=9;j++) {    ++tn;
        Link (tn,i);
    }} sum=81;
        for (int i=1;i<=9;i++)//each row {tn= (i-1) *81;
            for (int k=1;k<=9;k++) {int tk=tn+k;
                for (int j=1;j<=9;j++) {link (tk,sum+ (i-1) *9+k);
            tk+=9;
    }} sum+=81;
        for (int i=1;i<=9;i++) {tn= (i-1) *9;
            for (int k=1;k<=9;k++) {int tk=tn+k;
                for (int j=1;j<=9;j++) {link (tk,sum+ (i-1) *9+k);
            tk+=81;
    }} sum+=81;
    int tt=0;
            for (int i1=1;i1<=3;i1++) {for (int j1=1;j1<=3;j1++) {tn= (i1-1) *81*3+9*3* (j1-1);
                for (int k=1;k<=9;k++) {++tt;
                int tk;
              for (int i=1;i<=3;i++)  {for (int j=1;j<=3;j++) {tk=tn+ (i-1) *81+9* (j-1) +k;
                    Link (TK,SUM+TT);
    }}}} void remove (int s) {l[r[s]]=l[s];
    r[L[s]]=r[s];
            for (int i=d[s];i!=s;i=d[i]) (int j=r[i];j!=i;j=r[j]) {u[d[j]]=u[j];
            D[U[J]]=D[J];
        num[save[j]]--;
    } void Resume (int s) {r[l[s]]=s;
    L[r[s]]=s;
            for (int i=u[s];i!=s;i=u[i]) (int j=l[i];j!=i;j=l[j]) {u[d[j]]=j;
            D[u[j]]=j;
        num[save[j]]++;
    } void Dfs (int s) {if (flag) return;
        if (r[head]==head) {flag=1;
            for (int i=0;i<s;i++) {int ti,tj,tk;
            int tans=save1[ans[i]]-1;
            Ti= (tans)/81+1;
            tj= (tans%81)/9+1;;
            tk= (tans%81)%9+1; printf ("<%d%d> ", TI,TJ);
        g[ti][tj]=tk+ ' 0 ';
    } return;
    int mi=inf,tu;
            for (int i=r[head];i!=head;i=r[i]) if (Mi>num[i]) {mi=num[i];
        Tu=i;
    Remove (TU);
        for (int i=d[tu];i!=tu;i=d[i]) {for (int j=r[i];j!=i;j=r[j]) remove (save[j]);
        Ans[s]=i;
        DFS (S+1);
    for (int j=l[i];j!=i;j=l[j]) resume (save[j]);
} resume (TU);
    int main () {int T;
    scanf ("%d", &t);
        while (t--) {build ();
        int tu=0;
                for (int i=1;i<=9;i++) {for (int j=1;j<=9;j++) {cin>>g[i][j];
                    if (g[i][j]!= ' 0 ') {int kk=g[i][j]-' 0 ';
                    Remove (save[H[TU+KK]]);
                    for (int i1=r[H[TU+KK]];i1!= h[tu+kk];i1=r[i1]) {remove (SAVE[I1));
     }           } tu+=9;
        }} flag=0;
        DFS (0);
        printf ("\ n");
            for (int i=1;i<=9;i++) {for (int j=1;j<=9;j++) printf ("%c", G[i][j]);
        printf ("\ n");
} return 0;
 }