10   for(
int y=1; y<=9; ++y) {
 
   11     for(
int x=9; x>=1; --x) {
 
   24   for (
int cx=1; cx<=9; ++cx) {
 
   25     for (
int cy=1; cy<=9; ++cy) {
 
   26       const int min_x = 
std::max(1, cx - 2);
 
   27       const int max_x = 
std::min(9, cx + 2);
 
   28       const int min_y = 
std::max(1, cy - 2);
 
   29       const int max_y = 
std::min(9, cy + 2);
 
   32       for (
int x=min_x; x<=max_x; ++x) {
 
   33         for (
int y=min_y; y<=max_y; ++y) {
 
   45   for (
int cx=1; cx<=9; ++cx) {
 
   46     for (
int cy=1; cy<=9; ++cy) {
 
   47       const int min_x = 
std::max(1, cx - 1);
 
   48       const int max_x = 
std::min(9, cx + 1);
 
   49       const int min_y = 
std::max(1, cy - 1);
 
   50       const int max_y = 
std::min(9, cy + 1);
 
   53       for (
int x=min_x; x<=max_x; ++x) {
 
   54         for (
int y=min_y; y<=max_y; ++y) {
 
   66   for (
int cx=1; cx<=9; ++cx) {
 
   67     for (
int cy=1; cy<=9; ++cy) {
 
   69       const int min_x = 
std::max(1, center.
x() - 2);
 
   70       const int max_x = 
std::min(9, center.
x() + 2);
 
   71       const int min_y = 
std::max(1, center.
y() - 1);
 
   72       const int max_y = 
std::min(9, center.
y() + 1);
 
   75       for (
int x=min_x; x<=max_x; ++x) {
 
   76         for (
int y=min_y; y<=max_y; ++y) {