void
place(Chip *c)
{
register Pin *p;
Chip *cp;
int i;
putpkg(c);
if(!(c->flags&IGRECT)){
if(cp = rectadd(c)){
if(!quiet)
fprint(2, "chip %s: rect collision with %s\n",
c->name, cp->name);
unplace(c);
return;
}
}
if(!(c->flags&IGPINS)){
for(i = 0, p = c->pins; i < c->npins; i++, p++)
if(pinlook(XY(p->p.x, p->p.y), 0) == 0){
if(!quiet)
fprint(2, "pin %s.%d[%p]; no pinhole\n",
c->name, i+c->pmin, p->p);
unplace(c);
return;
}
}
}
/**
* Same as before, but perform alpha-beta pruning.
* The main routine should make the call with
* alpha = COMP_LOSS and beta = COMP_WIN.
*/
int TicTacToe::findCompMove( int & bestMove, int alpha, int beta )
{
int i, responseValue;
int dc; // dc means don't care; its value is unused
int value;
if( fullBoard( ) )
value = DRAW;
else
if( immediateCompWin( bestMove ) )
return COMP_WIN; // bestMove will be set by immediateCompWin
else
{
value = alpha; bestMove = 1;
for( i = 1; i <= 9 && value < beta; i++ ) // Try each square
{
if( isEmpty( i ) )
{
place( i, COMP );
responseValue = findHumanMove( dc, value, beta );
unplace( i ); // Restore board
if( responseValue > value )
{
// Update best move
value = responseValue;
bestMove = i;
}
}
}
}
return value;
}