Sudoku Game source code

[Goyalaayush22]

#include <stdio.h>
#include <stdlib.h>

#define SIZE 9
#define get_low_bit(x) ((~x&(x-1))+1)

struct{
int left;
char num;
char try;
}board[SIZE][SIZE];

int bit2num(int bit)
{
switch(bit){
case 1:case 2:
return bit;
case 4:
return 3;
case 8:
return 4;
case 16:
return 5;
case 32:
return 6;
case 64:
return 7;
case 128:
return 8;
case 256:
return 9;
}
}

void printf_res()
{
int i, j, k;

for(i=0; i<SIZE; i++)
{
if(i%3==0)
{
for(j=0; j<SIZE*2+4; j++)
putchar('-');
putchar('\n');
}

for(j=0; j<SIZE; j++)
{
if(j%3==0)
putchar('|');
if(board[i][j].num > 0)
printf("3[0;31m%2d3[0m", board[i][j].num);
else
printf("%2d", board[i][j].try);
}
printf("|\n");
}
for(i=0; i<SIZE*2+4; i++)
putchar('-');
putchar('\n');
}

void sub(int i, int j, int bit)
{
int k, m;

for(k=0; k<SIZE; k++)
{
board[k][j].left &= ~bit;
board[i][k].left &= ~bit;
}

for(k=i/3*3; k<(i/3+1)3; k++)
for(m=j/33; m<(j/3+1)*3; m++)
board[k][m].left &= ~bit;
}

void init()
{
int i, j;

for(i=0; i<SIZE; i++)
for(j=0; j<SIZE; j++)
if(board[i][j].num > 0)
sub(i, j, 1<<(board[i][j].num-1));
else if(board[i][j].try > 0)
sub(i, j, 1<<(board[i][j].try-1));
}

void add(int i, int j, int bit)
{
int k, m;

for(k=0; k<SIZE; k++)
{
board[k][j].left |= bit;
board[i][k].left |= bit;
}
for(k=i/3*3; k<(i/3+1)3; k++)
for(m=j/33; m<(j/3+1)*3; m++)
board[k][m].left |= bit;
}

void solve(int pos)
{
int i=pos/SIZE;
int j=pos%SIZE;
int bit, left;

if(pos == SIZE*SIZE)
{
printf_res();
exit(0);
}
if(board[i][j].num > 0)
solve(pos+1);
else
for(left=board[i][j].left; left; left&=(left-1))
{
bit = get_low_bit(left);
sub(i, j, bit);
board[i][j].try = bit2num(bit);

solve(pos+1);

add(i, j, bit);
board[i][j].try=0;
init();
}
}

int main()
{
int i, j, c;

for(i=0; i<SIZE; i++)
for(j=0; j<SIZE; j++)
{
while((c=getchar())<'0' || c>'9')
;
board[i][j].num = c-'0';
board[i][j].try = 0;
board[i][j].left = 0x0001FF;
}
init();
solve(0);

return 0;
}