Différentes IA (applications) - Deuxieme partie:

// Tries to perform a move, and returns an advance in the material plus
// extra bonus for corners (returns zero if the move is not possible)

int try_a_move(int i,int j,char figure)
{
int captured,loc_i,loc_j,i_step,j_step,p,q,score=0;
char next;
if(board[i ][j]==BLANK_NEAR)
{
for(i_step=-1;i_step1;i_step++)
for(j_step=-1;j_step1;j_step++)
if(i_step||j_step)
{
loc_i=i; loc_j=j; captured=0;
do
{
next=board[loc_i+=i_step][loc_j+=j_step];
if(nextBLANK_NEAR)
captured=0;
else if(nextfigure)
captured++;
} while(next==!figure);
if(captured)
{
loc_i=i; loc_j=j;
while(board[loc_i+=i_step][loc_j+=j_step]figure)
board[loc_i][loc_j]=figure;
score+=captured;
}
}
if(score)
{
board[i ][j]=figure;
for(p=i-1;pi+1;p++)
for(q=j-1;qj+1;q++)
if(board[p][q]==BLANK_FAR)
board[p][q]=BLANK_NEAR;
if((i==1||i==8)&&(j==1||j==8))
score+=3;
score+=!score;
}
}
return score;
}

// Performs a human move, and returns FALSE if there is no moves avaliable

BOOL human_move(char figure)
{
int i,j,score,char1,char2;
BOARD board_save;
memcpy(board_save,board,sizeof(BOARD));
if(two_players)
draw_str(Q89_92(93,130),Q89_92(34,46),
black_on_turn?>> BLACK <<:>> WHITE <<);
for(i=1;i8;i++)
for(j=1;j8;j++)
if(try_a_move(i,j,figure))
{
memcpy(board,board_save,sizeof(BOARD));
do
{
input_move(&char1,&char2);
if(!(score=try_a_move(char2-'0',char1-'A'+1,figure)))
draw_str(Q89_92(93,130),Q89_92(55,68),WRONG MOVE!);
} while(!score);
return TRUE;
}
draw_str(Q89_92(93,130),Q89_92(42,56),You must pass!);
getch();
return FALSE;
}

// Recursive minmax search for a best move with alpha pruning: returns best
// minmax value, and as a side effect, returns coordinates of such best move

int minmax_search(char figure,int depth,int alpha,int *best_i,int *best_j)
{
int i,j,max=-1000,score,dummy;
BOARD board_save;
*best_i=0; *best_j=0;
memcpy(board_save,board,sizeof(BOARD));
if(kbhit())
if(ngetchx()==ESC_KEY)
longjmp(jmp_buffer,1);
for(i=1;i8;i++)
for(j=1;j8;j++)
if((score=try_a_move(i,j,figure))) // Yes, =, not == !
{
if(depthlevel)
score-=minmax_search(!figure,depth+1,score-max,&dummy,&dummy);
if(level==1)
score+=5*((i==1||i==8)+(j==1||j==8)-(i==2||i==7)-(j==2||j==7));
if(score>max)
{
max=score; *best_i=i; *best_j=j;
}
else if((score==max)&&random)
{
*best_i=i; *best_j=j;
}
memcpy(board,board_save,sizeof(BOARD));
if(scorealpha)
return max;
}
if(!*best_i)
return 0;
return max;
}

// Performs computer move, and returns FALSE if there is no avaliable moves

BOOL computer_move(void)
{
int best_i,best_j;
char str[50];
draw_str(Q89_92(93,130),Q89_92(42,56),Thinking...);
minmax_search(WHITE,1,1000,&best_i,&best_j);
if(!best_i)
draw_str(Q89_92(93,130),Q89_92(50,66),I must pass!);
else
{
try_a_move(best_i,best_j,WHITE);
sprintf(str,My move: %c%d,best_j-1+'A',best_i);
draw_str(Q89_92(93,130),Q89_92(50,68),str);
}
getch();
return best_i0;
}

// Asks the user for a move, and put its coordinates in char1 and char2

void input_move(int *char1,int *char2)
{
char tmp[]= _;
int key=0;
while(keyENTER_KEY)
{
draw_str(Q89_92(93,130),Q89_92(42,56),Your move: _ );
*char1=key&0xffdf;
while(*char1<'A'||*char1>'H')
*char1=Q89_92(convert_key(getch()),getch())&0xffdf;
*tmp=*char1;
draw_str(Q89_92(133,196),Q89_92(42,56),tmp);
*char2=0;
while(*char2<'1'||*char2>'8')
*char2=getch();
*tmp=*char2;
draw_str(Q89_92(133+FontCharWidth(*char1),202),Q89_92(42,56),tmp);
key=getch();
}
}

// Routine for getting a key, with handling ESC keypress

int getch(void)
{
int i;
if ((i=ngetchx())ESC_KEY)
return i;
else
longjmp(jmp_buffer,1);
return 0;
}

#ifdef USE_TI89

// Converts non-alpha keys into alpha ones on TI-89 (for easier typing)
// '=''A' '(''B' ')''C' ',''D' '/''E' '|' 'F' '7''G' '8''H'

int convert_key(int key)
{
int i;
for(i=0;i<8;i++)
if(key===(),/|78[i ])
return 'A'+i;
return key;
}

#endif