211 lines
5.9 KiB
Fortran
211 lines
5.9 KiB
Fortran
C fortran version of proving you can't win at tic-tac-toe if the opponent is competent
|
|
C constants:
|
|
C score win: 6
|
|
C score tie: 5
|
|
C score lose: 4
|
|
C score max: 9
|
|
C score min: 2
|
|
C piece X: 1
|
|
C piece O: 2
|
|
C piece blank: 0
|
|
|
|
program ttt
|
|
integer*4 moves
|
|
integer*2 b(9), sp(10), sv(10), sa(10), sb(10), sm(10)
|
|
integer*2 mc, l
|
|
integer*2 alpha, beta, wi, st, sc, v, p, pm, m
|
|
common /area/ b,sp,sv,sa,sb,sm,mc,alpha,beta,wi,st,sc,v,p,pm,m
|
|
|
|
integer*2 system
|
|
|
|
do 6 l = 1, 9, 1
|
|
b( l ) = 0
|
|
6 continue
|
|
|
|
moves = 0
|
|
|
|
do 10 l = 1, 10, 1
|
|
C do 10 l = 1, 1, 1
|
|
mc = 0
|
|
m = 1
|
|
call runmm
|
|
m = 2
|
|
call runmm
|
|
m = 5
|
|
call runmm
|
|
moves = moves + mc
|
|
10 continue
|
|
|
|
write( *, 20 ) moves
|
|
20 format( ' moves: ', I6 )
|
|
end
|
|
|
|
1000 subroutine runmm
|
|
integer*2 b(9), sp(10), sv(10), sa(10), sb(10), sm(10)
|
|
integer*2 mc, l
|
|
integer*2 alpha, beta, wi, st, sc, v, p, pm, m
|
|
common /area/ b,sp,sv,sa,sb,sm,mc,alpha,beta,wi,st,sc,v,p,pm,m
|
|
|
|
alpha = 2
|
|
beta = 9
|
|
p = m
|
|
b(m) = 1
|
|
call minmax
|
|
b(m) = 0
|
|
return
|
|
end
|
|
|
|
2000 subroutine winner
|
|
integer*2 b(9), sp(10), sv(10), sa(10), sb(10), sm(10)
|
|
integer*2 mc, l
|
|
integer*2 alpha, beta, wi, st, sc, v, p, pm, m
|
|
common /area/ b,sp,sv,sa,sb,sm,mc,alpha,beta,wi,st,sc,v,p,pm,m
|
|
|
|
wi = b( 1 )
|
|
if ( 0 .eq. wi ) go to 2100
|
|
if ( ( wi .eq. b( 2 ) ) .and. ( wi .eq. b( 3 ) ) ) return
|
|
if ( ( wi .eq. b( 4 ) ) .and. ( wi .eq. b( 7 ) ) ) return
|
|
2100 wi = b( 4 )
|
|
if ( 0 .eq. wi ) go to 2200
|
|
if ( ( wi .eq. b( 5 ) ) .and. ( wi .eq. b( 6 ) ) ) return
|
|
2200 wi = b( 7 )
|
|
if ( 0 .eq. wi ) go to 2300
|
|
if ( ( wi .eq. b( 8 ) ) .and. ( wi .eq. b( 9 ) ) ) return
|
|
2300 wi = b( 2 )
|
|
if ( 0 .eq. wi ) go to 2400
|
|
if ( ( wi .eq. b( 5 ) ) .and. ( wi .eq. b( 8 ) ) ) return
|
|
2400 wi = b( 3 )
|
|
if ( 0 .eq. wi ) go to 2500
|
|
if ( ( wi .eq. b( 6 ) ) .and. ( wi .eq. b( 9 ) ) ) return
|
|
2500 wi = b( 5 )
|
|
if ( 0 .eq. wi ) return
|
|
if ( ( wi .eq. b( 1 ) ) .and. ( wi .eq. b( 9 ) ) ) return
|
|
if ( ( wi .eq. b( 3 ) ) .and. ( wi .eq. b( 7 ) ) ) return
|
|
wi = 0
|
|
end
|
|
|
|
4000 subroutine minmax
|
|
integer*2 b(9), sp(10), sv(10), sa(10), sb(10), sm(10)
|
|
integer*2 mc, l
|
|
integer*2 alpha, beta, wi, st, sc, v, p, pm, m
|
|
common /area/ b,sp,sv,sa,sb,sm,mc,alpha,beta,wi,st,sc,v,p,pm,m
|
|
|
|
st = 0
|
|
v = 0
|
|
4100 mc = mc + 1
|
|
if ( st .lt. 4 ) go to 4150
|
|
C the computed goto is about 20% faster than calling winner
|
|
C call winner
|
|
go to ( 5010, 5020, 5030, 5040, 5050, 5060, 5070, 5080, 5090 ), p
|
|
4110 if ( wi .eq. 0 ) go to 4140
|
|
if ( wi .ne. 1 ) go to 4130
|
|
sc = 6
|
|
go to 4280
|
|
4130 sc = 4
|
|
go to 4280
|
|
4140 if ( st .ne. 8 ) go to 4150
|
|
sc = 5
|
|
go to 4280
|
|
4150 if ( b( p ) .eq. 1 ) go to 4160
|
|
v = 2
|
|
pm = 1
|
|
go to 4170
|
|
4160 v = 9
|
|
pm = 2
|
|
4170 p = 1
|
|
4180 if ( b( p ) .ne. 0 ) go to 4500
|
|
b( p ) = pm
|
|
4182 st = st + 1
|
|
sp( st ) = p
|
|
sv( st ) = v
|
|
sa( st ) = alpha
|
|
sb( st ) = beta
|
|
sm( st ) = pm
|
|
go to 4100
|
|
4280 p = sp( st )
|
|
v = sv( st )
|
|
alpha = sa( st )
|
|
beta = sb( st )
|
|
pm = sm( st )
|
|
st = st - 1
|
|
b( p ) = 0
|
|
if ( pm .eq. 1 ) go to 4340
|
|
if ( sc .eq. 4 ) go to 4530
|
|
if ( sc .lt. v ) v = sc
|
|
if ( v .lt. beta ) beta = v
|
|
if ( beta .le. alpha ) go to 4520
|
|
go to 4500
|
|
4340 if ( sc .eq. 6 ) go to 4530
|
|
if ( sc .gt. v ) v = sc
|
|
if ( v .gt. alpha ) alpha = v
|
|
if ( alpha .ge. beta ) go to 4520
|
|
4500 p = p + 1
|
|
if ( p .lt. 10 ) go to 4180
|
|
4520 sc = v
|
|
4530 if ( st .eq. 0 ) return
|
|
go to 4280
|
|
|
|
5010 wi = b(1)
|
|
if ( ( wi .eq. b(2) ) .and. ( wi .eq. b(3) ) ) goto 4110
|
|
if ( ( wi .eq. b(4) ) .and. ( wi .eq. b(7) ) ) goto 4110
|
|
if ( ( wi .eq. b(5) ) .and. ( wi .eq. b(9) ) ) goto 4110
|
|
wi = 0
|
|
go to 4110
|
|
|
|
5020 wi = b(2)
|
|
if ( ( wi .eq. b(1) ) .and. ( wi .eq. b(3) ) ) goto 4110
|
|
if ( ( wi .eq. b(5) ) .and. ( wi .eq. b(8) ) ) goto 4110
|
|
wi = 0
|
|
go to 4110
|
|
|
|
5030 wi = b(3)
|
|
if ( ( wi .eq. b(1) ) .and. ( wi .eq. b(2) ) ) goto 4110
|
|
if ( ( wi .eq. b(6) ) .and. ( wi .eq. b(9) ) ) goto 4110
|
|
if ( ( wi .eq. b(5) ) .and. ( wi .eq. b(7) ) ) goto 4110
|
|
wi = 0
|
|
go to 4110
|
|
|
|
5040 wi = b(4)
|
|
if ( ( wi .eq. b(5) ) .and. ( wi .eq. b(6) ) ) goto 4110
|
|
if ( ( wi .eq. b(1) ) .and. ( wi .eq. b(7) ) ) goto 4110
|
|
wi = 0
|
|
go to 4110
|
|
|
|
5050 wi = b(5)
|
|
if ( ( wi .eq. b(1) ) .and. ( wi .eq. b(9) ) ) goto 4110
|
|
if ( ( wi .eq. b(3) ) .and. ( wi .eq. b(7) ) ) goto 4110
|
|
if ( ( wi .eq. b(2) ) .and. ( wi .eq. b(8) ) ) goto 4110
|
|
if ( ( wi .eq. b(4) ) .and. ( wi .eq. b(6) ) ) goto 4110
|
|
wi = 0
|
|
go to 4110
|
|
|
|
5060 wi = b(6)
|
|
if ( ( wi .eq. b(4) ) .and. ( wi .eq. b(5) ) ) goto 4110
|
|
if ( ( wi .eq. b(3) ) .and. ( wi .eq. b(9) ) ) goto 4110
|
|
wi = 0
|
|
go to 4110
|
|
|
|
5070 wi = b(7)
|
|
if ( ( wi .eq. b(8) ) .and. ( wi .eq. b(9) ) ) goto 4110
|
|
if ( ( wi .eq. b(1) ) .and. ( wi .eq. b(4) ) ) goto 4110
|
|
if ( ( wi .eq. b(5) ) .and. ( wi .eq. b(3) ) ) goto 4110
|
|
wi = 0
|
|
go to 4110
|
|
|
|
5080 wi = b(8)
|
|
if ( ( wi .eq. b(7) ) .and. ( wi .eq. b(9) ) ) goto 4110
|
|
if ( ( wi .eq. b(2) ) .and. ( wi .eq. b(5) ) ) goto 4110
|
|
wi = 0
|
|
go to 4110
|
|
|
|
5090 wi = b(9)
|
|
if ( ( wi .eq. b(7) ) .and. ( wi .eq. b(8) ) ) goto 4110
|
|
if ( ( wi .eq. b(3) ) .and. ( wi .eq. b(6) ) ) goto 4110
|
|
if ( ( wi .eq. b(1) ) .and. ( wi .eq. b(5) ) ) goto 4110
|
|
wi = 0
|
|
go to 4110
|
|
|
|
end
|
|
|
|
|