5. To Parent Links

• In later versions of Freecell Solver, each state contains a pointer to its "parent state" - the first state from which it was discovered.
• I eventually realized I could add a move stack of moves that lead from the parent to it, thus enabling FCS to trace the solution of a state by collecting all the moves to the initial state.
• This resulted in shorter solutions, making the optimization scan almost completely unnecessary.

Written by Shlomi Fish