delete pics to save space

p.CH2901.cpp

@@ -0,0 +1,128 @@
+//http://contest-hunter.org:83/contest/0x29%E3%80%8C%E6%90%9C%E7%B4%A2%E3%80%8D%E7%BB%83%E4%B9%A0/2901%20%E9%9D%B6%E5%BD%A2%E6%95%B0%E7%8B%AC
+#include<cstdio>
+#include<cstring>
+#include<vector>
+#include<cassert>
+using namespace std;
+const int maxn=81*4+5;
+const int maxnode=9*9*9*4*4+5;
+int res=-1;
+const int p[9][9]=
+{
+{6,6,6,6,6,6,6,6,6},
+{6,7,7,7,7,7,7,7,6},
+{6,7,8,8,8,8,8,7,6},
+{6,7,8,9,9,9,8,7,6},
+{6,7,8,9,10,9,8,7,6},
+{6,7,8,9,9,9,8,7,6},
+{6,7,8,8,8,8,8,7,6},
+{6,7,7,7,7,7,7,7,6},
+{6,6,6,6,6,6,6,6,6}
+};
+const int Slot=0;
+const int Row=1;
+const int Col=2;
+const int Sub=3;
+inline int encode(int a,int b,int c) { return a*81+b*9+c+1; }
+inline void decode(int code,int &a,int &b,int &c)
+{
+    code--;
+    c=code%9; code/=9;
+    b=code%9; code/=9;
+    a=code;
+}
+struct DLX
+{
+    int n,sz;
+    int s[maxn];
+    int row[maxnode],col[maxnode];
+    int L[maxnode],R[maxnode],U[maxnode],D[maxnode];
+    void init(int n)
+    {
+        this->n=n;
+        sz=n+1;
+        memset(s,0,sizeof(s));
+        
+        for(int i=0;i<=n;i++)
+            { U[i]=i; D[i]=i; L[i]=i-1; R[i]=i+1; } 
+        R[n]=0; L[0]=n;
+    }
+    void addNodes(int r,const vector<int> &columns)
+    {
+        int first=sz,c_sz=columns.size();
+        for(int i=0;i<c_sz;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;
+    }
+    
+    #define For(i,A,s) for(int i=A[s];i!=s;i=A[i])
+    void remove(int c)
+    {
+        L[R[c]]=L[c];
+        R[L[c]]=R[c];
+        For(i,D,c)
+            For(j,R,i)
+            { U[D[j]]=U[j]; D[U[j]]=D[j]; --s[col[j]]; }
+    }
+    void restore(int c)
+    {
+        For(i,U,c)
+            For(j,L,i)
+            { ++s[col[j]]; U[D[j]]=j; D[U[j]]=j; }
+        L[R[c]]=c;
+        R[L[c]]=c;
+    }
+    
+    bool dfs(int val)
+    {
+        if(R[0]==0) { res=max(res,val); return true; }
+        
+        int c=R[0],flag=false;
+        For(i,R,0) if(s[i]<s[c]) c=i;
+        
+        remove(c);
+        
+        For(i,D,c)
+        {
+            For(j,R,i) remove(col[j]);
+            int nr,nc,nv;
+            decode(row[i],nr,nc,nv);
+            if(dfs(val+p[nr][nc]*(nv+1))) flag=true;
+            For(j,L,i) restore(col[j]);
+        }
+        restore(c);
+        
+        return flag;
+    }
+    #undef For
+};
+DLX solver;
+int mp[9][9];
+#define For(i,a,b) for(int i=(a);i<=(b);i++)
+int main()
+{
+#ifdef local
+    freopen("pro.in","r",stdin);
+#endif
+    For(r,0,8) For(c,0,8) scanf("%d",&mp[r][c]);
+    solver.init(9*9*4);
+    For(r,0,8) For(c,0,8) For(v,0,8)
+        if(mp[r][c]==0||mp[r][c]==v+1)
+        {
+            vector<int> cols;
+            cols.push_back(encode(Slot,r,c));
+            cols.push_back(encode(Row,r,v));
+            cols.push_back(encode(Col,c,v));
+            cols.push_back(encode(Sub,(r/3)*3+c/3,v));
+            solver.addNodes(encode(r,c,v),cols);
+        }
+    solver.dfs(0);
+    printf("%d\n",res);
+    return 0;
+}