delete pics to save space

7.3074.cpp

@@ -0,0 +1,62 @@
+#include<cstdio>
+#include<cstring>
+#include<algorithm>
+#include<cassert>
+using namespace std;
+char buf[100],mp[9][9];
+int rc[9],cc[9],bx[3][3],lg[2000],ct[2000];
+bool dfs(int lst)
+{
+	if(lst==0) return true;
+	int nr=-1,nc=-1,ncnt=10;
+	for(int r=0;r<9;r++) for(int c=0;c<9;c++)
+	{
+		if(mp[r][c]) continue;
+		int can=rc[r]&cc[c]&bx[r/3][c/3];
+		if(ct[can]<ncnt) nr=r,nc=c,ncnt=ct[can];
+	}
+	for(int can=rc[nr]&cc[nc]&bx[nr/3][nc/3];can;can-=(can&-can))
+	{
+		int now=lg[can&-can];
+		mp[nr][nc]=now;
+		rc[nr]^=1<<now;
+		cc[nc]^=1<<now;
+		bx[nr/3][nc/3]^=1<<now;
+		assert(1<=now&&now<=9);
+		if(dfs(lst-1)) return true;
+		mp[nr][nc]=0;
+		rc[nr]^=1<<now;
+		cc[nc]^=1<<now;
+		bx[nr/3][nc/3]^=1<<now;
+	}
+	return false;
+}
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	for(int i=1;i<=9;i++) lg[1<<i]=i;
+	ct[1]=1;
+	for(int i=1;(i<<1)+1<2000;i++) { ct[(i<<1)+1]=ct[i]+1; ct[i<<1]=ct[i]; }
+	while(scanf("%s",buf),strcmp(buf,"end"))
+	{
+		for(int r=0;r<9;r++) for(int c=0;c<9;c++) mp[r][c]=buf[r*9+c];
+		memset(rc,0,sizeof(rc)); memset(cc,0,sizeof(cc)); memset(bx,0,sizeof(bx));
+		for(int i=0;i<9;i++) for(int j=1;j<=9;j++) rc[i]|=1<<j;
+		for(int i=0;i<9;i++) for(int j=1;j<=9;j++) cc[i]|=1<<j;
+		for(int i=0;i<3;i++) for(int j=0;j<3;j++) for(int k=1;k<=9;k++) bx[i][j]|=1<<k;
+		int tot=0;
+		for(int r=0;r<9;r++) for(int c=0;c<9;c++)
+		{
+			if(mp[r][c]=='.') { mp[r][c]=0; tot++; continue; }
+			mp[r][c]-='0';
+			rc[r]^=(1<<mp[r][c]);
+			cc[c]^=(1<<mp[r][c]);
+			bx[r/3][c/3]^=(1<<mp[r][c]);
+		}
+		assert(dfs(tot));
+		for(int r=0;r<9;r++) for(int c=0;c<9;c++) putchar(mp[r][c]+'0'); puts("");
+	}
+	return 0;
+}