/**
* Tests a move and returns a list containing the move.
*/
func testMove(state *util.BoardState, move util.Move) *list.List {
l := list.New()
lR := util.GetRow(move.NewPosition)
if lR < 0 || lR >= util.GetNumberOfRows() {
return l
}
lD := util.GetDisplacement(move.NewPosition)
if 0 <= lR && lR <= util.GetNumberOfRows() && 0 <= lD && lD <= lR {
b := state.Board[move.OriginalPosition] && !state.Board[move.NewPosition] && state.Board[move.RemovePiece]
if b {
l.PushFront(move)
}
}
return l
}
/**
* Gets the list of all available moves of the given peg.
*/
func getValidMovesForPosition(state *util.BoardState, peg int) *list.List {
validMoves := list.New()
r := util.GetRow(peg)
d := util.GetDisplacement(peg)
/**
* There are only 6 possible directions the peg can jump based on the diagram below.
*
* 6 1
* 5 0 2
* 4 3
*/
// Direction 1
land := util.GetPegNumber(r-2, d)
jump := util.GetPegNumber(r-1, d)
validMoves.PushBackList(testMove(state, util.Move{peg, land, jump}))
// Direction 2
land = util.GetPegNumber(r, d+2)
jump = util.GetPegNumber(r, d+1)
validMoves.PushBackList(testMove(state, util.Move{peg, land, jump}))
// Direction 3
land = util.GetPegNumber(r+2, d+2)
jump = util.GetPegNumber(r+1, d+1)
validMoves.PushBackList(testMove(state, util.Move{peg, land, jump}))
// Direction 4
land = util.GetPegNumber(r+2, d)
jump = util.GetPegNumber(r+1, d)
validMoves.PushBackList(testMove(state, util.Move{peg, land, jump}))
// Direction 5
land = util.GetPegNumber(r, d-2)
jump = util.GetPegNumber(r, d-1)
validMoves.PushBackList(testMove(state, util.Move{peg, land, jump}))
// Direction 6
land = util.GetPegNumber(r-2, d-2)
jump = util.GetPegNumber(r-1, d-1)
validMoves.PushBackList(testMove(state, util.Move{peg, land, jump}))
return validMoves
}