/* Code for exercise 15.3.
|
| "C++ Solutions--Companion to The C++ Programming Language, Third Edition"
| by David Vandevoorde; Addison-Wesley 1998; ISBN 0-201-30965-3.
|
| Permission to use, copy, modify, distribute and sell this software
| and its documentation for any purpose is hereby granted without fee.
| The author makes no representations about the suitability of this
| software for any purpose. It is provided "as is" without express or
| implied warranty.
`----------------------------------------------------------------------*/
#include "VirtualPlayer.H"
#include <limits>
void VirtualPlayer::get_move(Board const &board,
int &row, int &col) {
int best = std::numeric_limits<int>::min(),
worst = std::numeric_limits<int>::max();
row = col = 0;
for (int r = 1; r!=Board::kNRows+1; ++r)
for (int c = 1; c!=Board::kNCols+1; ++c)
if (board.valid_move(color_, r, c)) {
int score = eval_self(board, r, c,
best, worst, 1);
if (score>=best) {
best = score;
row = r; col = c;
}
}
}
int VirtualPlayer::eval_self(Board const &board,
int row, int col,
int best, int worst, int d) {
if (d==maxdepth_) // Maximum depth of exploration?
return value_of(board);
Board copy(board);
if (row>0)
copy.move(color_, row, col);
bool move_result = kUnsuccessful;
for (int r = 1; r!=Board::kNRows+1; ++r)
for (int c = 1; c!=Board::kNCols+1; ++c)
if (copy.valid_move(opponent_of(color_), r, c)) {
move_result = kSuccessful;
int score = eval_opponent(copy, r, c,
best, worst, d+1);
if (score<=best) // This won't get any better:
return score; // "prune" this branch now.
if (score<worst)
worst = score;
}
if (move_result==kSuccessful)
return worst;
else // The opponent had no valid response
if (copy.get_possible_move(color_, row, col)
==kSuccessful)
return eval_opponent(copy, 0, 0, best, worst, d+1);
else // We reached an end-of-game situation
return eval_end_of_game(copy);
}
int VirtualPlayer::eval_opponent(Board const &board,
int row, int col,
int best, int worst, int d)
{
if (d==maxdepth_) // Maximum depth of exploration reached?
return value_of(board);
Board copy(board);
if (row>0) // Row==0 when we have no valid move
copy.move(opponent_of(color_), row, col);
bool move_result = kUnsuccessful;
// Explore own possible responses:
for (int r = 1; r!=Board::kNRows+1; ++r)
for (int c = 1; c!=Board::kNCols+1; ++c)
if (copy.valid_move(color_, r, c)) {
move_result = kSuccessful;
int score = eval_self(copy, r, c,
best, worst, d+1);
if (score>=worst) // This won't get any better:
return score; // "prune" this branch now.
if (score>best)
best = score;
}
if (move_result==kSuccessful)
return best;
else // We have no valid response
if (copy.get_possible_move(opponent_of(color_),
row, col)==kSuccessful)
return eval_self(copy, 0, 0, best, worst, d+1);
else // We reached an end-of-game situation
return eval_end_of_game(copy);
}
int VirtualPlayer::eval_end_of_game(Board const &board) {
if (board.score(color_)
>board.score(opponent_of(color_)))
return std::numeric_limits<int>::max()-1;
if (board.score(color_)
>board.score(opponent_of(color_)))
return std::numeric_limits<int>::min()+1;
else
return 0; // The value of a tie could be biased
} // if desired.
namespace { // unnamed namespace
int corner_value(Color player, Color corner,
Color p1, Color p2, Color p3) {
Color opp = opponent_of(player);
if (corner==player)
return 30;
if (corner==opp)
return -30;
int value = 0;
if ((p1==player) || (p2==player) || (p3==player))
value -= 30;
if ((p1==opp) || (p2==opp) || (p3==opp))
value += 30;
return value;
}
} // end unnamed namespace
int VirtualPlayer::value_of(Board const &s) {
Color opponent = opponent_of(color_);
// First component: material advantage
int value = s.score(color_)-s.score(opponent);
// Second component: corner positions
int t = 1, l = 1, r = Board::kNCols, b = Board::kNRows;
value += corner_value(color_, s(t, l),
s(t+1, l), s(t, l+1), s(t+1, l+1));
value += corner_value(color_, s(t, r),
s(t+1, r), s(t, r-1), s(t+1, r-1));
value += corner_value(color_, s(b, r),
s(b-1, r), s(b, r-1), s(b-1, r-1));
value += corner_value(color_, s(b, l),
s(b-1, l), s(b, l+1), s(b-1, l+1));
return value;
}
《The c++ programming language 》的习题答案 （122个子文件） 
VirtualPlayer.C 5KB Board.C 3KB HumanTextPlayer.C 2KB VirtualTextPlayer.C 2KB Game.C 1KB BoardTextViewer.C 1KB Reversi.C 1KB ex22_8b.cpp 5KB ex17_1.cpp 5KB ex8_1.cpp 5KB ex13_2.cpp 5KB ex7_19.cpp 4KB ex6_16.cpp 4KB ex14_2.cpp 3KB ex12_10.cpp 3KB ex15_2.cpp 3KB ex17_6.cpp 3KB ex8_10.cpp 3KB ex4_3a.cpp 3KB ex10_12b.cpp 3KB ex6_22.cpp 3KB ex10_19.cpp 3KB ex21_2.cpp 3KB ex18_19.cpp 3KB ex10_12a.cpp 3KB ex21_13.cpp 3KB ex6_12.cpp 2KB ex7_7.cpp 2KB ex22_8a.cpp 2KB ex11_1.cpp 2KB ex20_15.cpp 2KB ex5_8.cpp 2KB ex18_10.cpp 2KB ex25_5.cpp 2KB ex19_1.cpp 2KB ex25_19.cpp 2KB ex14_1.cpp 2KB ex8_6.cpp 2KB ex4_3b.cpp 2KB ex10_5.cpp 2KB ex16_6.cpp 2KB ex17_3.cpp 2KB ex18_5.cpp 2KB ex18_1.cpp 2KB ex6_3.cpp 2KB ex21_12.cpp 2KB ex21_18.cpp 2KB ex7_16.cpp 2KB ex18_14.cpp 2KB ex20_5.cpp 2KB ex21_24.cpp 2KB ex6_10.cpp 2KB ex5_11.cpp 2KB ex14_10.cpp 2KB ex11_4.cpp 2KB ex20_1.cpp 2KB ex5_13.cpp 2KB ex19_2.cpp 2KB ex4_4.cpp 1KB ex22_1.cpp 1KB ex16_2.cpp 1KB ex16_3.cpp 1KB ex5_6.cpp 1KB ex22_2a.cpp 1KB ex7_11.cpp 1KB ex22_2b.cpp 1KB ex12_9.cpp 1KB ex22_4.cpp 1KB ex8_7.cpp 1KB ex4_6.cpp 1KB ex21_1.cpp 1KB ex5_12.cpp 1KB ex5_10a.cpp 1KB ex18_11.cpp 1KB ex16_1.cpp 1KB ex6_13.cpp 1KB ex7_9.cpp 1KB ex20_16.cpp 1KB ex11_8.cpp 1KB ex25_7.cpp 1KB ex4_5.cpp 1KB ex6_17.cpp 1KB ex5_4.cpp 1KB ex5_7b.cpp 1KB ex12_1a.cpp 1KB ex5_7a.cpp 1KB ex8_5.cpp 1KB ex12_1b.cpp 1KB ex11_21.cpp 1014B ex7_4.cpp 941B ex13_15.cpp 934B ex5_10b.cpp 904B ex6_7.cpp 898B ex7_18.cpp 883B ex6_14.cpp 822B ex7_3.cpp 820B ex10_15.cpp 807B ex11_10.cpp 781B ex8_4.cpp 766B ex5_9.cpp 731B共 122 条
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资源评论
yuyeshijie2012-09-05答案还不错，能够和题相关！
wuhanmobile2013-03-12答案还不错- sun01282014-02-11真不错，可以帮助检验一下对这本书的理解。
- sh33514292013-01-04答案很好，可以参考学习
- fulin12345672011-10-25很不错，程序可以运行
