Commit 8c9b82d4 authored by Vít Novotný's avatar Vít Novotný
Browse files

added example 7.1_11

parent 122091d7
% nacteni:
/* ['7.1_11.pl']. */
% minimax( Pos, BestSucc, Val ):
% Pos is a position , Val is its minimax value ;
% best move from Pos leads to position BestSucc
minimax(Pos, BestSucc, Val) :-
moves(Pos, PosList), ! , % Legal moves in Pos produce PosList
best(PosList, BestSucc, Val)
;
staticval( Pos, Val ). % Pos has no successors : evaluate statically
best([Pos], Pos, Val) :-
minimax(Pos,_, Val), ! .
best([Pos1 | PosList], BestPos, BestVal) :-
minimax(Pos1,_, Val1),
best(PosList, Pos2, Val2),
betterof(Pos1, Val1, Pos2, Val2, BestPos, BestVal).
betterof(Pos0, Val0, _Pos1, Val1, Pos0, Val0) :- % Pos0 better than Pos1
min_to_move(Pos0), % MIN to move in Pos0
Val0 > Val1, ! % MAX prefers the greater value
;
max_to_move(Pos0), % MAX to move in Pos0
Val0 < Val1, ! . % MIN prefers the lesser value
betterof(_Pos0, _Val0, Pos1, Val1, Pos1, Val1). % Otherwise Pos1 better than Pos0
#!/usr/bin/env python
# encoding=utf-8 (pep 0263)
from linked_lists import LinkedList, Nil
def minimax(pos):
poslist = moves(pos)
if poslist == Nil:
return (None, staticval(pos))
return best(poslist)
def best(poslist):
pos1 = poslist.head
if poslist.tail == Nil:
return minimax(pos1)
_, val1 = minimax(pos1)
pos2, val2 = best(poslist.tail)
return better_of(pos1, val1, pos2, val2)
def better_of(pos0, val0, pos1, val1):
if min_to_move(pos0) and val0 > val1 or max_to_move(pos0) and val0 < val1:
return (pos0, val0)
return (pos1, val1)
start = "root"
graph = dict(
root=("max", LinkedList(["a1", "a2", "a3"])),
a1=("min", LinkedList(["b1", "b2", "b3"])),
a2=("min", LinkedList(["c1", "c2", "c3"])),
a3=("min", LinkedList(["d1", "d2", "d3"])),
b1=("max", Nil), b2=("max", Nil), b3=("max", Nil),
c1=("max", Nil), c2=("max", Nil), c3=("max", Nil),
d1=("max", Nil), d2=("max", Nil), d3=("max", Nil))
def moves(pos):
# zavisi na resenem problemu
return graph[pos][1]
def min_to_move(pos):
return graph[pos][0] == "min"
def max_to_move(pos):
return graph[pos][0] == "max"
staticvals = dict(
b1=3, b2=12, b3=8,
c1=2, c2=4, c3=6,
d1=14, d2=5, d3=2)
def staticval(pos):
# zavisi na resenem problemu
if pos not in staticvals:
raise ValueError("Uzel %s neni cilovy." % pos)
return staticvals[pos]
# demonstracni vypis
if __name__ == "__main__":
print("Minimax - hra na jedno kolo\n")
print(" root ")
print(" a1 a2 a3 ")
print("b1 b2 b3 c1 c2 c3 d1 d2 d3\n")
print(" 3 12 8 2 4 6 14 5 2\n")
print("Vysledek volani minimax('root'): %s" % (minimax("root"),))
Minimax - hra na jedno kolo
root
a1 a2 a3
b1 b2 b3 c1 c2 c3 d1 d2 d3
3 12 8 2 4 6 14 5 2
Vysledek volani minimax('root'): ('a1', 3)
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