Sudoku game
Topic link: Sudoku game
Title description
Problem solving ideas
This question is obviously a deep search.
Three arrays are used to store the used numbers in the current row, column, and grid respectively.
Then search.
code
#include<iostream>
#include<cstdio>
#include<string>
#include<cstring>
using namespace std;
string T;
int ok;
int a[10][10];
int h[10][10],l[10][10],g[4][4][10];
int ch(int t)
{
if(t<=3)
return 1;
if(t>3&&t<=6)
return 2;
if(t>6&&t<=9)
return 3;
}
void dfs(int x,int y)
{
if(ok)
return;
if(x>9&&y==1)
{
for(int i=1;i<=9;i++)
for(int j=1;j<=9;j++)
cout<<a[i][j];
ok=1;
return;
}
if(a[x][y])
{
if(y==9)
dfs(x+1,1);
else
dfs(x,y+1);
}
else for(int i=1;i<=9;i++)
if(!h[x][i]&&!l[y][i]&&!g[ch(x)][ch(y)][i])
{
a[x][y]=i;
h[x][i]=1;
l[y][i]=1;
g[ch(x)][ch(y)][i]=1;
if(y==9)
dfs(x+1,1);
else
dfs(x,y+1);
a[x][y]=0;
h[x][i]=0;
l[y][i]=0;
g[ch(x)][ch(y)][i]=0;
}
}
int main()
{
while(cin>>T)
{
if(T=="end")
return 0;
for(int i=1;i<=9;i++)
for(int j=1;j<=9;j++)
{
if(T[(i-1)*9+j-1]>='0'&&T[(i-1)*9+j-1]<='9')
{
a[i][j]=T[(i-1)*9+j-1]-'0';
h[i][a[i][j]]=1;
l[j][a[i][j]]=1;
g[ch(i)][ch(j)][a[i][j]]=1;
}
else
a[i][j]=0;
}
ok=0;
dfs(1,1);
cout<<endl;
memset(a,0,sizeof(a));
memset(h,0,sizeof(h));
memset(l,0,sizeof(l));
memset(g,0,sizeof(g));
}
}