| Procedure PiecesDistanceCalculation |
| Input: |
| PS, the current pieces-state. |
| , piece . |
| , piece . |
| Output: |
| Dab, the distance between and . |
| Method: |
| ()let CS be the checkers-state; |
| () let vAllFC be a vector to store the falling checkers of every layer. |
| () //The maximum distance between and . |
| () Calculate the move distance MDab; |
| () if MDab == 0 or MDab == 1 or MDab == 2 then |
| () //If MDab is less than 3, there is no less distance. |
| () return MDab; |
| () endif |
| () for = 0 to 9 do |
| () CS[PS⋅SAS[]⋅][PS⋅SAS[]⋅] = 1; |
| () CS[PS⋅SPS[]⋅][PS⋅SPS[]⋅] = −1; |
| () endfor |
| () FindVirtualFallingCheckers(0, CS, , , true, vAllFC, 0); |
| () isBreak = false; //Denotes the end of searching. |
| () Dab = MDab; //The distance in the worst case. |
| () for each allFC in vAllFC do |
| () for each in allFC do |
| () if allFC.index == (MDab −1) then |
| () isBreak = true; break; |
| () endif |
| () if == and == then |
| () Dab = allFC.index + 1; isBreak = true; |
| () break; |
| () endif |
| () if allFC.index == (MDab −2) then break; endif |
| () FindVirtualFallingCheckers(0, CS, , , true, vAllFC, allFC.index + 1); |
| () endfor |
| () if isBreak == true then break; endif |
| () endfor |
| () return Dab; |
| () //Search the virtual falling checkers of specified checkers. |
| () Function FindVirtualFallingCheckers(, CS, , , isFirstStep, vAllFC, index) |
| () begin |
| () for = 3to−3 do |
| () if == − then continue; endif |
| () if == 0 then continue; endif |
| () Search the next jumping falling checker (, ) in direction of checker (, ). |
| () if (, ) exists then |
| () vAllFC[index].add(new Coordinate(, )); |
| () FindVirtualFallingCheckers(3, CS, , , false, vAllFC, index); |
| () else if the piece on (, ) is of own side then |
| () FindVirtualFallingCheckers(3, CS, , , true, vAllFC, index + 1); |
| () else |
| () if isFirstStep == true then |
| () vAllFC[index].add(new Coordinate(, )); |
| () endif |
| () endif |
| () endfor |
| () end |
