iSudokuSolver Support Page

This application will help you solve that "difficult" puzzle. It provides an easy initial position setup. You can then step through the solution one cell at a time or you can let the application step through it for you. The screen initially shows a sudoku grid with no cells solved.

Initial View. Below the grid are four buttons:
  • start - once the problem has been completely entered, click to set the initial position. The step and solve buttons are then enabled.
  • step - solve one cell.
  • solve - automatically step through the solution.
  • clear - clears the grid.
To set a value for a cell, tap the cell and a larger grid view of the possible cell values is displayed. Tap a value to set the value for the chosen cell. To reset a cell tap a '.'. To return without updating the cell click the close button. Initial View.
Initial View. Once the problem has been entered click the "start" button.
The label of the start button will change to "reset" and the step and solve buttons will enable. Clicking the "reset"button will restore the grid to the initial position. Initial View.
Initial View. Clicking "step" will solve a cell and stop. The solved cell is highlighted in yellow for a couple of seconds and a "click" is played. As cells are solved, the solution is display in green and the other cells are updated to remove values that are no longer possible. There is a message area below the grid which will shows the number of cells solved and the number of alternatives being tried.
Clicking solve will step through the solution with a short delay between each step until the final solution is arrived at. The background of all the cells is set to red for a short period. Initial View.

Simpler problems can be solved by a process of elimation. The process of elimination involves removing from a cell the values of the solved cells in the same row, column and quadrant. This will often yield a cell which only has one possible value left. You can then remove this value from cells in the same row, column and quadrant. There may be one cell in a row, column or quadrant which is the only cell to contain a possible value. You continue to repeat this process until the problem is solved or no more cells can be solved. In more difficult problems you arrive at a position where non of the above techniques will find any more cell solutions. You then have to pick a cell, preferably the one with the least number of possible values, repeat the above processes with each value in the chosen cell. In the extremely difficult problems there are more than one cell which requires this alternative choice evaluation. In this application where the solution reaches such a decision cell, the background of the cell is set to grey and the following solved cells are set to blue.

Initial View.

When a decision cell is reached the background of this cell is set to grey and the colour of the following solutions are blue. If a chose proves to be a dead end the board is reset to position it was at the start of the alternative process and the next chose is analysed. The reset will cause all the cells which were reset to flash yellow.

For other iPhone applications from ObjectGizmos Ltd check here


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