Task Lists

• sudoku solver.
• sudoku generator based on 1 seed.
• sudoku generator based on random seed.
• sudoku -> HTML DOM. result -> HTML DOM implementation will be carried out at later date.

The sudoku solver logic in the ./dump folder is usable. It requires some time to compute because it uses the backtracking strategy.

The current sudoku generator uses the swap, sort, shrink strategy. This approach require another strategy to solve without problem. It's not production ready.

Please feel free to make a PR to solve the current problem:

```
// debug only: ERROR vertical steps 2 needs new strategy
subGridRowLength = 2;
gridNestedArray = [
    [3, 2, 3, 1],
    [4, 1, 2, 4],
    [3, 4, 3, 1],
    [1, 2, 2, 4]
];

// debug only: ERROR vertical steps 1 needs new strategy
subGridRowlength = 2;
gridNestedArray = [
    [8,4,5,4,6,3,1,6,9],
    [3,1,2,9,8,7,4,8,3],
    [9,6,7,1,5,2,5,2,7],
    [2,3,4,6,7,3,1,9,8],
    [8,1,6,9,4,5,2,5,4],
    [7,5,9,8,1,2,7,3,6],
    [2,9,5,4,9,8,3,2,8],
    [7,1,3,3,1,7,4,6,5],
    [6,4,8,5,6,2,9,7,1]
];
```

The Swap, Sort, Shrink Strategy

Swap: Only swap between unsorted with unsorted and sorted with sorted box.

Sort: See the diagram below, sorted row / column should not swap with different row / column.

Shrink: Horizontal -> Veritcal -> Horizontal -> repeat.

4x4
[┌, ─, ─, ─]
[|, ┌, ─, ─]
[|, |, ┌, ─|
[|, |, |,  ]

9x9
X ┌, ─, ─, X ─, ─, ─, X ─, ─, ─ X
X |, ┌, ─, X ─, ─, ─, X ─, ─, ─ X
X |, |, ┌, X ─, ─, ─, X ─, ─, ─ X
X----------+----------+---------X
X |, |, |, X ┌, ─, ─, X ─, ─, ─ X
X |, |, |, X |, ┌, ─, X ─, ─, ─ X
X |, |, |, X |, |, ┌, X ─, ─, ─ X
X----------+--------+-----------X
X |, |, |, X |, |, |, X ┌, ─, ─ X
X |, |, |, X |, |, |, X |, ┌, ─ X
X |, |, |, X |, |, |, X |, |    X

Functions

• newGrid(subGridRowLength) to populate valid Sudoku.