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Sudokusolver.cpp
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Sudokusolver.cpp
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/*This work is licensed under a Creative Commons Attribution 4.0 International License
view http://creativecommons.org/licenses/by/4.0/ for further details*/
/*Gowtham Rangarjan*/
/*SudoKu solver*/
#include<iostream>
#include<fstream>
#include <stdarg.h>
#include <stdlib.h>
#include<stdio.h>
#include <time.h>
using namespace std;
#define SUDOKU_SIZE 9
#define END 13 /*Bit position that is used to indicate the cell to be filled*/
#define INPUTFILE "sudoku.in"
#define OUTPUTFILE "Solver.out"
#define UNITTESTFILE "Manysudoku.in"
#define CLEARBIT(x,v) (x&(~(1<<(v))))
#define COPY_STATE(dest,src) \
{\
for(int _i=0;_i<SUDOKU_SIZE;_i++)\
for(int _j=0;_j<SUDOKU_SIZE;_j++)\
dest[_i][_j] = src[_i][_j];\
}
#define VERBOSE(flg ,format, ...)\
if(flg)\
printf("Verbose mode ON ...:"format"\n");\
#define UPPER_BOUND 25
#define LOWER_BOUND 5
/*Function prototypes*/
long long solvesudoku(unsigned int a[][SUDOKU_SIZE], unsigned int output[][SUDOKU_SIZE]);
unsigned int iscomplete(unsigned int output[][SUDOKU_SIZE]);
void fill(unsigned int value, unsigned int r, unsigned int c,unsigned int output[][SUDOKU_SIZE]);
unsigned int fillup(unsigned int output[][SUDOKU_SIZE]);
void print_output_array(unsigned int output[SUDOKU_SIZE][SUDOKU_SIZE],...);
int backtrack(unsigned int output[][SUDOKU_SIZE]);
/*Unit Test*/
void unitTest();
bool generatePuzzles(unsigned int a[][SUDOKU_SIZE],int seed,int blocks);
/*Helper*/
void interpretoutput(unsigned int src[SUDOKU_SIZE][SUDOKU_SIZE] , unsigned int dest[SUDOKU_SIZE][SUDOKU_SIZE]);
int verifypuzzle(unsigned int a[SUDOKU_SIZE][SUDOKU_SIZE],int r,int c);
bool verbose =false;/*In case user needs more details*/
bool debug = false;/*In case of problems programmer*/
bool profiler=true;
/*
Pick random memorized solution from File
*/
void rotate90(unsigned int a[SUDOKU_SIZE][SUDOKU_SIZE]);
void reflect_horizontal(unsigned int a[SUDOKU_SIZE][SUDOKU_SIZE]);
void reflect_vertical(unsigned int a[SUDOKU_SIZE][SUDOKU_SIZE]);
void relabel(unsigned int a[SUDOKU_SIZE][SUDOKU_SIZE]);
int randompermutor = 0;
int totalpermutor = 0;
void relabel(unsigned int a[SUDOKU_SIZE][SUDOKU_SIZE]){
unsigned int relabel[SUDOKU_SIZE];
//choose a random permutation
int swaps = SUDOKU_SIZE;
for(int i=0;i<SUDOKU_SIZE;i++)
relabel[i]=i;
//Truly random ?
for(int i=0;i<swaps;i++,totalpermutor++){
int r1 = rand()%(SUDOKU_SIZE)+1;
int r2 = SUDOKU_SIZE - rand()%(SUDOKU_SIZE);
while(r1==r2){
randompermutor++;
totalpermutor++;
r1 = rand()%(SUDOKU_SIZE)+1;
r2 = SUDOKU_SIZE - rand()%(SUDOKU_SIZE);
}
swap(relabel[r1],relabel[r2]);
}
for(int i=0;i<SUDOKU_SIZE;i++)
for(int j=0;j<SUDOKU_SIZE;j++){
a[i][j] = relabel[a[i][j]];
}
}
void rotate90(unsigned int a[SUDOKU_SIZE][SUDOKU_SIZE]){
unsigned temp[SUDOKU_SIZE][SUDOKU_SIZE];
for(int i=0;i<SUDOKU_SIZE;i++)
for(int j=0;j<SUDOKU_SIZE;j++)
temp[SUDOKU_SIZE-1-j][i] = a[i][j];
memcpy(a,temp,sizeof(temp));
}
void reflect_horizontal(unsigned int a[SUDOKU_SIZE][SUDOKU_SIZE]){
for(int i=0;i<SUDOKU_SIZE;i++)
for(int j=0;j<SUDOKU_SIZE/2;j++)
swap(a[i][j],a[SUDOKU_SIZE-1-i][j]);
}
void reflect_vertical(unsigned int a[SUDOKU_SIZE][SUDOKU_SIZE]){
for(int i=0;i<SUDOKU_SIZE;i++)
for(int j=0;j<SUDOKU_SIZE/2;j++)
swap(a[i][j],a[i][SUDOKU_SIZE-1-j]);
}
void unitTest(){
for(int i=0;i<3000;i++){
unsigned int a[SUDOKU_SIZE][SUDOKU_SIZE];
unsigned int output[SUDOKU_SIZE][SUDOKU_SIZE];
unsigned int interpret[SUDOKU_SIZE][SUDOKU_SIZE];
memset(a,0,sizeof(a));
memset(output,0,sizeof(interpret));
memset(interpret,0,sizeof(interpret));
int blocksfilled = 0;
/*Generating random number between lower and upper bound*/
blocksfilled = ((rand()%(UPPER_BOUND-LOWER_BOUND)))+LOWER_BOUND;
int n;
ifstream fin;
fin.open(UNITTESTFILE);
fin>>n;
while(n--){
for(int k=0;k<SUDOKU_SIZE;k++){
for(int l=0;l<SUDOKU_SIZE;l++){
fin>>a[k][l];
//cout<<"Hello"<<endl;
}
}
//cout<<"Done reading sol"<<endl;
if(!generatePuzzles(a,((i*i)^(i)),blocksfilled))
continue;
/*if(verbose){
cout<<"Printing after generation"<<endl;
print_output_array(a);
}*/
print_output_array(a,"UnitTestinputSudoku.in");
long long timetaken =time(NULL);
timetaken-= solvesudoku(a,interpret);
//PROFILE();
if(profiler){
FILE* fp = fopen("prof.txt","ab");
fprintf(fp,"%d,%d,%lld\n",i,blocksfilled,timetaken);
fclose(fp);
}
interpretoutput(interpret,output);
/*if(verbose){
cout<<"Printing after solving"<<endl;
print_output_array(output);
}*/
print_output_array(output,"UnitTestOutputSudoKu.out");
}
}
}
bool generatePuzzles(unsigned int a[][SUDOKU_SIZE],int seed,int blocks) {
srand ( seed );
unsigned int temp[SUDOKU_SIZE][SUDOKU_SIZE];
memset(a,0,sizeof(a));
memset(temp,0,sizeof(temp));
int incorrect;
int times = 0;
int numberofoperations = (rand()%(SUDOKU_SIZE*10));
//cout<<"Random operations !"<<numberofoperations<<endl;
while(numberofoperations--){
switch (rand()%4){
case (0):{
//cout<<"Random operations 0"<<endl;
rotate90(a);
break;
}
case (1):
//cout<<"Random operations 1"<<endl;
reflect_vertical(a);
break;
case (2):
//cout<<"Random operations 2"<<endl;
reflect_horizontal(a);
break;
case (3):
//cout<<"Relabeling"<<endl;
relabel(a);
break;
}
}
//cout<<"Done"<<endl;
for(int i=0;i<blocks;i++){
int r = rand()%SUDOKU_SIZE;
int c = rand()%SUDOKU_SIZE;
temp[r][c] =a[r][c];
//cout<<"vallll "<<a[r][c]<<endl;
incorrect = verifypuzzle(a,r,c);
if(incorrect!=0){
a[r][c] = 0;
i--;
times++;
}
//cout<<"vallll out "<<a[r][c]<<endl;
if(times >= 100){
cout<<"unable to generate random puzzle"<<blocks<<endl;
return false;
}
}
return true;
}
int verifypuzzle(unsigned int a[SUDOKU_SIZE][SUDOKU_SIZE],int r,int c){
int incorrect = 0;
{
int i=r,j=c;
if(a[i][j]!=0) {
for(int k=0;k<SUDOKU_SIZE;k++)
if((a[k][j] == a[i][j] && k!=j)|| (a[i][k]==a[i][j] && k!=j)){
a[i][j]=0;
return 1;
}
for(int p=0;p<9;p++){
int r1 = 3*(i/3) +(p/3);
int c1 = 3*(j/3) + (p%3);
if((a[r1][c1] == a[i][j])&& r1!=i && j!=c1){
a[i][j] = 0;
//incorrect++;
return 1;
}
}
}
}
return incorrect;
}
/*Helper*/
/*
Usage:
fills a value in the grid , propagates constraints
*/
void fill(unsigned int value, unsigned int r, unsigned int c,unsigned int output[][SUDOKU_SIZE]){
for(unsigned int i=0;i<SUDOKU_SIZE;i++)
output[r][i] = CLEARBIT(output[r][i],value); /*clearing value th bit*/
for(unsigned int i=0;i<SUDOKU_SIZE;i++)
output[i][c] = CLEARBIT(output[i][c],value); /*clearing value th bit*/
unsigned int p=(r/3)*3 , q=(c/3)*3;
output[p][q] = CLEARBIT(output[p][q],value);
output[p][q+1] = CLEARBIT(output[p][q+1],value);
output[p][q+2] = CLEARBIT(output[p][q+2],value);
output[p+1][q] = CLEARBIT(output[p+1][q],value);
output[p+1][q+1] = CLEARBIT(output[p+1][q+1],value);
output[p+1][q+2] = CLEARBIT(output[p+1][q+2],value);
output[p+2][q] = CLEARBIT(output[p+2][q],value);
output[p+2][q+1] = CLEARBIT(output[p+2][q+1],value);
output[p+2][q+2] = CLEARBIT(output[p+2][q+2],value);
output[r][c] = (1<<value) | (1<<END);
}
/*Helper*/
/* Usage:
Traverses entire grid ,
Finds the first cell which can be ascertained with a certain value*/
unsigned int fillup(unsigned int output[][SUDOKU_SIZE]){
/*look for potential solutions*/
for(int i=0;i<SUDOKU_SIZE;i++){
for(int j=0;j<SUDOKU_SIZE;j++){
/*if a unique solution exists at
a location then its a output[i][j]
is a power of 2 !!*/
if(!(output[i][j]&(output[i][j]-1))){
/*mark a bit so that we
dont see it again*/
/*extract bit pos*/
int v = output[i][j];
int cnt=0;
/*counts the position of bits set*/
while(!(v&1)){
cnt++;
v/=2;
}
if(cnt == 13){
cout<<"Shouldnt Come here :( "<<endl;
return 0;
}else
fill(cnt,i,j,output);
//cout<<cnt<<endl;
return 1;
}
}
}
return 0;
}
/*The solver routine*/
long long solvesudoku(unsigned int a[][SUDOKU_SIZE], unsigned int output[][SUDOKU_SIZE]){
for(unsigned int i=0;i<SUDOKU_SIZE;i++){
for(unsigned int j=0;j<SUDOKU_SIZE;j++){
output[i][j] = (0x3FE & ~(1<<END));/*possible values bit-manip*/
}
}
for(unsigned int i=0;i<SUDOKU_SIZE;i++){
for(unsigned int j=0;j<SUDOKU_SIZE;j++){
if(a[i][j]!=0){
fill(a[i][j],i,j,output);
VERBOSE(verbose,"FILLING %u %u \n ",i,j);
if(debug)
print_output_array(output);
}
}
}
while(fillup(output)){
VERBOSE(verbose,"completing puzzle ...\r");
}
if(iscomplete(output)){
VERBOSE(verbose,"EASY PUZZLE :)\n");
}
else {
VERBOSE(verbose,"HARD PUZZLE .. proceeding with Backtracking search\n");
/*Backtracking + based on higher chances of success first*/
if(backtrack(output)){
VERBOSE(verbose,"SOLVEDPrinting RESULT\n");
}
else{
VERBOSE(verbose,"SOLVED Printing RESULT\n");
return -1;
}
}
return 0;
}
int backtrack(unsigned int output[][SUDOKU_SIZE]){
VERBOSE(verbose,"BACKTACKING ...\r");
/*Finding the best next guy*/
int lr=SUDOKU_SIZE,lc=SUDOKU_SIZE,t=0,pre_cnt =100;
for(unsigned int i=0;i<SUDOKU_SIZE;i++){
for(unsigned int j=0;j<SUDOKU_SIZE;j++){
if(!((output[i][j]>>END) &1)){
int v = output[i][j];
int cnt = 1;
while((v&(v-1))){
v-=(v&(v-1));
cnt++;
}
lr = cnt<pre_cnt ? i:lr;
lc = cnt<pre_cnt ? j:lc;
pre_cnt = cnt<pre_cnt ? cnt:pre_cnt;
t++;
}
}
}
if(lr ==SUDOKU_SIZE || lc==SUDOKU_SIZE)
return 1;
/*extract lowest isolated bit*/
int v =output[lr][lc];
/*Checking for possible paths*/
for(int i=1;i<32;i++){
if((v>>i)&1){
unsigned int temp[SUDOKU_SIZE][SUDOKU_SIZE];
COPY_STATE(temp,output);
fill(i, lr, lc,temp);
if(!backtrack(temp))
continue;
else{
COPY_STATE(output,temp);
return 1;
}
}
}
return 0;
}
/*Helper*/
unsigned int iscomplete(unsigned int output[][SUDOKU_SIZE]){
for(unsigned int i=0;i<SUDOKU_SIZE;i++){
for(unsigned int j=0;j<SUDOKU_SIZE;j++){
unsigned int val = output[i][j];
val = val&~(1<<END);
if((val&(val-1)))
return 0;
}
}
return 1;
}
/*Helper*/
void print_output_array(unsigned int output[SUDOKU_SIZE][SUDOKU_SIZE],...){
char* filename = NULL;
va_list arguments;
va_start ( arguments, output);
filename = va_arg ( arguments, char* );
va_end ( arguments );
FILE* f = NULL;
//cout<<filename<<endl;
if(filename!= NULL) {
f = fopen(filename,"ab");
}
//ostream fout(buf,app);
if(f!= NULL) {
fprintf(f,"\n\n");
}
fprintf(stdout,"\n\n");
//fout<<endl<<endl<<endl;
for(unsigned int i=0;i<SUDOKU_SIZE;i++){
for(unsigned int j=0;j<SUDOKU_SIZE;j++){
//fout<<output[i][j]<<" ";
if(f!= NULL) {
fprintf(f,"%u ",output[i][j]);
}
fprintf(stdout,"%u ",output[i][j]);
}
//fout<<endl;
if(f!= NULL) {
fprintf(f,"\n");
}
fprintf(stdout,"\n");
}
if(f!= NULL) {
fprintf(f,"\n\n");
}
fprintf(stdout,"\n\n");
if(f!= NULL) {
//cout<<"closing"<<endl;
fclose(f);
}
}
void interpretoutput(unsigned int src[SUDOKU_SIZE][SUDOKU_SIZE] , unsigned int dest[SUDOKU_SIZE][SUDOKU_SIZE]){
memset(dest,0,sizeof(dest));
for(unsigned int i=0;i<SUDOKU_SIZE;i++){
for(unsigned int j=0;j<SUDOKU_SIZE;j++){
int flg =0;
for(int _p=1;_p<=SUDOKU_SIZE;_p++){
if(!(src[i][j]& ~(1<<END | 1<<_p))){
dest[i][j] = _p;
//fout<<_p;
flg=1;
break;
}
}
if(!flg)
dest[i][j] = 0;
}
}
}
void usage(){
cout<<endl<<endl<<"USAGE :: executible <options,one or many>"<<endl;
cout<<"Options (all are case sensitive)"<<endl;
cout<<" -h : Help , this menu"<<endl;
cout<<" -UnitTest :Run unit test on sudoku solver "<<endl;
cout<<" -V :Verbose mode ON "<<endl;
cout<<" -ProfilerOFF : Run Profiler calculate the time taken write into prof.txt in the same location as the executible [Switched on by default]"<<endl;
cout<<endl<<endl;
}
int main(int argc , char* argv[]){
profiler = true;
verbose = false;
if(argc>1){
for(int i=1;i<argc;i++){
if(memcmp(argv[i],"-ProfilerOFF",sizeof(char)*12) == 0)
profiler = false;
if(memcmp(argv[i],"-V",sizeof(char)*2) == 0)
verbose = true;
if(memcmp(argv[i],"-h",sizeof(char)*2) == 0){
usage();
return 0;
}
if(memcmp(argv[i],"-UnitTest",sizeof(char)*9) == 0){
unitTest();
cout<<"Randompermutor totalpermutor"<<randompermutor<<" "<<totalpermutor<<endl;
return 0;
}
}
}
ifstream fin;
ofstream fout;
fin.open(INPUTFILE);
fout.open(OUTPUTFILE);
unsigned int n;
fin>>n;
srand ( time(NULL) );
int random_number = rand();
while(n--) {
fout<<endl<<endl;
unsigned int a[SUDOKU_SIZE][SUDOKU_SIZE];
memset(a,0,sizeof(a));
for(unsigned int i=0;i<SUDOKU_SIZE;i++)
for(unsigned int j=0;j<SUDOKU_SIZE;j++)
fin>>a[i][j];
unsigned int intermediateOutput[SUDOKU_SIZE][SUDOKU_SIZE];
unsigned int output[SUDOKU_SIZE][SUDOKU_SIZE];
memset(intermediateOutput,0,sizeof(intermediateOutput));
memset(output,0,sizeof(output));
long long timetaken =time(NULL);
timetaken -=solvesudoku(a,intermediateOutput);
interpretoutput(intermediateOutput,output);
for(int i=0;i<SUDOKU_SIZE;i++){
for(int j=0;j<SUDOKU_SIZE;j++)
fout<<output[i][j]<<" ";
fout<<endl;
}
}
fin.close();
fout.close();
return 0;
}