Poj3074-sudoku (Sudoku DLX)

Test instructions: Give a 9*9 matrix, some grids have been filled in, some are. Represents not filled in. Ask any set of solutions so that each row contains 1~9, each column contains 1~9, and each small rectangle (3*3) contains 1~9.

Resolution: Accurate coverage of DLX classic topics, each line represents the case to be filled, a total of 81*4 rows, the first 81 lines represent the line I J column number, the second 81 column represents the first row of the number K, the third 81 column

The number k is placed on behalf of Column J, and the fourth 81 line represents the first small rectangle in the second. For cases where the character is. Add 9 rows and one row for the case where the character is a number. And then just run, DLX, save the answer.

Output can be.

Code

#include <cstdio>#include<cstring>#include<string>#include<algorithm>using namespacestd;Const intinf=1e9+7;Const intms=Bayi*Ten;Const intmaxn=ms*4;intANS[MAXN];structdlx{intN,id; intL[MAXN],R[MAXN],U[MAXN],D[MAXN]; intc[maxn],s[maxn],loc[maxn][3]; intH[ms]; voidInitintnn=0) {n=nn;  for(intI=0; i<=n;i++) u[i]=d[i]=i,l[i]=i-1, r[i]=i+1; l[0]=n; r[n]=0; ID=N; memset (S),0,sizeof(S)); memset (H,-1,sizeof(H)); }    voidLink (intXintYintPxintPyintk) {++ID; D[id]=y; u[id]=U[y]; D[u[y]]=id; u[y]=ID; loc[id][0]=px,loc[id][1]=py,loc[id][2]=K; C[id]=y; s[y]++; if(h[x]==-1) h[x]=l[id]=r[id]=ID; Else        {            intA=H[x]; intb=R[a]; L[id]=a; r[a]=ID; R[id]=b; l[b]=ID; H[X]=ID; }    }    voidRemove (intc) {L[r[c]]=L[c]; R[L[C]]=R[c];  for(intI=d[c];i!=c;i=D[i]) for(intj=r[i];j!=i;j=R[j]) {U[d[j]]=U[j]; D[U[J]]=D[j]; S[C[J]]--; }    }    voidResume (intc) { for(intI=u[c];i!=c;i=U[i]) for(intj=r[i];j!=i;j=R[j]) {S[c[j]]++; U[D[J]]=J; D[U[J]]=J; } L[r[c]]=C; R[L[C]]=C; }    BOOLDfsintStep) {        if(step==Bayi)return true; if(r[0]==0)return false; intmin=inf,c=-1;  for(inti=r[0];i;i=R[i])if(Min>s[i]) {Min=s[i]; c=i;}        Remove (c);  for(intI=d[c];i!=c;i=D[i]) {Ans[step]=i;  for(intj=r[i];j!=i;j=R[j])            Remove (C[j]); if(Dfs (step+1))return true;  for(intj=l[i];j!=i;j=L[j])        Resume (C[j]);        } Resume (c); return false; }}DLX;intMain () {Chars[ -];  while(SCANF ("%s", S)! =EOF) {        if(s[0]=='e') Break; Dlx.init (Bayi*4); intk=0, r=0;  for(intx=0;x<9; x + +)             for(inty=0;y<9; y++)        {            Charch=s[k++]; inta,b,c,d; if(ch=='.')            {                 for(intI=1; i<=9; i++) {a=x*9+y+1; b=x*9+i+Bayi; C=y*9+i+Bayi+Bayi; intS= (x/3)*3+y/3; D=s*9+i+Bayi+Bayi+Bayi; ++R; Dlx.                    Link (R,a,x,y,i); Dlx.                    Link (R,b,x,y,i); Dlx.                    Link (R,c,x,y,i); Dlx.                Link (R,d,x,y,i); }            }            Else            {                inti=ch-'0'; A=x*9+y+1; b=x*9+i+Bayi; C=y*9+i+Bayi+Bayi; intS= (x/3)*3+y/3; D=s*9+i+Bayi+Bayi+Bayi; ++R; Dlx.                Link (R,a,x,y,i); Dlx.                Link (R,b,x,y,i); Dlx.                Link (R,c,x,y,i); Dlx.            Link (R,d,x,y,i); }} Dlx.dfs (0); intres[Ten][Ten];  for(intI=0;i<Bayi; i++)        {            intA=Ans[i]; intx=dlx.loc[a][0],y=dlx.loc[a][1],k=dlx.loc[a][2]; Res[x][y]=K; }         for(intI=0;i<9; i++)             for(intj=0;j<9; j + +) printf ("%d", Res[i][j]); printf ("\ n"); }    return 0;}

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Poj3074-sudoku (Sudoku DLX)