Greetings--
Until I saw your posting I had never heard of Sodoku before. I think I may be addicted now. Your original problem of generating random puzzles began to bother me once I started playing. It was driving me crazy. Here is a solution for you. The function, when called, returns the puzzle in a 2D array. I hope it will be of some use to you.
function suduko(){
var i,j, q, opt, row, spot, weak, current, tmp, badFlag;
var scramble= function(arr){ //returns array in scrambled order
var i, len,obj,sorter, rnd, res;
obj = {};
sorter = [];
res = [];
len = arr.length;
i = 0;
while(i < len){
rnd = Math.random() + "";
if(obj[rnd]){
continue;
}
obj[rnd] = arr[i];
i++;
sorter.push(rnd);
}
sorter = sorter.sort();
for(i = 0; i < len; i++){
res.push(obj[sorter[i]]);
}
return res;
}
//=================================
var join = function(a1, a2){ //joins two arrays but strains out duplicate values
var arr, i, len, v;
arr = a1.concat(a2);
len = arr.length;
for(i = 0;i< len; i++){
v = arr.shift();
if(arr.indexOf(v) != -1){
continue;
}
arr.push(v);
}
return arr;
}
var getColumn = function(off){ //gets all values in the specified column
var i, arr, v;
arr = [];
for(i = 0; i < 9; i++){
v = q[i][off];
if(v != 0){
arr.push(v);
}
}
return arr;
}
var getRow = function(off){//gets all values in a row
var i, arr, v;
arr = [];
for(i = 0; i < 9; i++){
v = q[off][i];
if(v != 0){
arr.push(v);
}
}
return arr;
}
var invert =function(arr){ //gives all values that are NOT in the argument array
var i, res, b = [1,2,3,4,5,6,7,8,9];
b = scramble(b);
res = [];
for(i = 0; i < 9; i++){
if(arr.indexOf(b[i]) == -1){
res.push(b[i]);
}
}
return res;
}
var getGrid =function(col,row){ //gives all the current values in the 3X3 box to which it belongs
var res, i,j, v;
jmp = [0,3,6,9];
res = [];
col = Math.floor(col/3);
col = jmp[col];
row = Math.floor(row/3);
row = jmp[row];
for(i =row; i < (row + 3); i++){
for(j = col; j < (col + 3);j++){
v = q[i][j];
if(res.indexOf(v) == -1 && v != 0){
res.push(v);
}
}
}
return res;
}
var getSet= function(c,r){ //get all current possible valid options for the position
var a, b, c;
a = getGrid(c,r);
b = getRow(r);
c = getColumn(c);
a = join(a,b);
a = join(a,c);
a =invert(a);
return a;
}
var init = function(){ //build the 2D array and set all values to zero
var i, j;
q = [];
for(i = 0; i < 9; i++){
q[i] = [];
for(j =0; j < 9; j++){
q[i][j] = 0;
}
}
}
//======== loop until the heuristic provides a valid puzzle
do{
init();
opt = scramble([1,2,3,4,5,6,7,8,9]);
for(i = 0;i < 9; i++){
q[0][i] = opt[i];
}
opt = opt.slice(3,9);
opt = scramble(opt);
for(i = 0; i < 3; i++){
q[1][i] = opt[i];
q[2][i] = opt[(i + 3)];
}
badFlag = false;
for(row = 1; row < 9; row++){
while(1 == 1){
tmp = getRow(row);
if(tmp.length == 9){
break;
}
weak = 10;
for(i = 0; i < 9;i++){
if(q[row][i] != 0){
continue;
}
tmp = getSet(i, row);
if(tmp.length < weak){
weak = tmp.length;
spot = i;
}
}
current = getSet(spot, row);
if(current.length == 0){ //heuristic failed--try again
badFlag = true;
break;
}
tmp = current.pop();
q[row][spot] = tmp;
}
if(badFlag){
break;
}
} //end of row
}while (badFlag);
//==================
return q;
}
var c = suduko();
console.log(c);
