# Step X Step Soln

This screen is used to apply the solution algorithms one at a time in the order you chose.
The algorithms are:
1. Only one possible location in a Shape
2. Only 1 possibility in a Cell
3. N possible solutions in N Cells in a Shape
4. Intersection of Overlapping Shapes
5. Check Partitions (Killer only)
6. Record Solutions
Algorithms 1 and 2 identify the next solutions. They do not eliminate possibilities from Cells.
Algorithms 3, 4, 5 eliminate possibilities from Cells. They do not identify solutions, e.g. if there is only one remaining possibility in a Cell – this requires a run of algorithm 2.
Algorithm 6 records the solution(s) that were identified by algorithms 1 and/or 2. In doing so they eliminate possibilities in other Cells.
The number of solutions waiting to be recorded is shown in the bottom left box. There are possibilities to record these one at a time or all together.
The “Detail to display” radio buttons select between:
 None Only shows solved Cells in the solution window. Shows the location, but not the value or character of the next waiting solution Next Solution As above but also shows the Character of the next waiting solution All As above plus shows remaining possible Characters in each Cell of the solution grid (often called “markup”). Working As above plus details of the elimination of possibilities in algorithms 3 and 4
The button “Highlight all Solutions” toggles between highlighting all solutions identified and waiting to be recorded and highlighting just the next solution.
There are a number of counters to track progress as follows:
 Possibilities removed Number of possibilities that were removed by the last algorithm, or during setup (e.g introduction of initial values) Total possibilities removed Possibilities removed from the start of the problem Possibilities remaining Strictly number of excess possibilities. Problem is solved when there is exactly one possibility in each Cell. These are not counted in this total. Cells solved Number of solutions recorded since the start of the problem Cells remaining unsolved Problem is solved when this = 0