// 无害裁剪
int HarmlessPruning ( void ) {
// 1. 和局局面
if ( pos.IsDraw() ) {
return 0; // eleeye上表示，为了安全起见，不用pos.DrawValue()
}
// 2. 路径重复
const int vRep = roll.RepStatus ();
if ( vRep != REP_NONE ) {
return roll.RepValue ( vRep );
}
return - MATE_VALUE;
}
// 尝试某个着法，并返回着法状态，参阅"cchess.h"
bool TryMove(PositionStruct &pos, int &nStatus, int mv) {
if (!pos.LegalMove(mv)) {
nStatus = MOVE_ILLEGAL;
return false;
}
if (!pos.MakeMove(mv)) {
nStatus = MOVE_INCHECK;
return false;
}
nStatus = 0;
nStatus += (pos.LastMove().CptDrw > 0 ? MOVE_CAPTURE : 0);
nStatus += (pos.LastMove().ChkChs > 0 ? MOVE_CHECK : 0);
nStatus += (pos.IsMate() ? MOVE_MATE : 0);
nStatus += pos.RepStatus(3) * MOVE_PERPETUAL; // 提示：参阅"position.cpp"中的"IsRep()"函数
nStatus += (pos.IsDraw() ? MOVE_DRAW : 0);
pos.UndoMakeMove();
return true;
}
// 无害裁剪
static int HarmlessPruning(const PositionStruct &pos, int vlBeta) {
int vl, vlRep;
// 1. 杀棋步数裁剪；
vl = pos.nDistance - MATE_VALUE;
if (vl >= vlBeta) {
return vl;
}
// 2. 和棋裁剪；
if (pos.IsDraw()) {
return 0; // 安全起见，这里不用"pos.DrawValue()";
}
// 3. 重复裁剪；
vlRep = pos.RepStatus();
if (vlRep > 0) {
return pos.RepValue(vlRep);
}
return -MATE_VALUE;
}
// 主搜索函数
int SearchMain ( void ) {
// 特殊情况
MoveSortStruct mvsort;
int nMoveNum = mvsort.InitMove ();
if ( nMoveNum == 0 ) { // 无着法
printf ( "bestmove a0a1 resign\n" );
fflush ( stdout );
return 0;
}
else if ( nMoveNum == 1 ) { // 唯一着法
printf ( "bestmove %s\n", MoveIntToStr(mvsort.move[0]).c_str() );
fflush ( stdout );
return mvsort.move[0];
}
if ( pos.IsDraw() ) { // 和局
printf ( "bestmove a0a1 draw\n" );
fflush ( stdout );
// 注意不要return
}
// 初始化
ClearHistoryTable ();
ClearHashTable ();
ClearHashTableQC ();
InitBeginTime ( SEARCH_TOTAL_TIME );
// 迭代加深搜索
printf("depth time nNode rBeta");
for ( int i = 0; i < 3; i ++ ) {
printf(" bvl[%d] bmv[%d]", i, i);
}
printf("\n");
fflush ( stdout );
int lastbvl[nBest], lastbmv[nBest];
ClearBmvBvl ( lastbmv, lastbvl );
for ( int depth = 1; /*depth <= ?*/; depth ++ ) {
InitBeginTime ( THIS_SEARCH_TIME );
InitSearchStruct ();
SearchAlphaBeta ( depth, - MATE_VALUE, MATE_VALUE );
if ( TimeOut() ) {
CopyBmvBvl ( Search.bmv, Search.bvl, lastbmv, lastbvl );
break;
}
else {
CopyBmvBvl ( lastbmv, lastbvl, Search.bmv, Search.bvl );
}
printf( "%5d %.2fs %7d %2.0f%%", depth, TimeCost(SEARCH_TOTAL_TIME), Search.nNode, 100.0*Search.nBeta/Search.nNode);
for ( int i = 0; i < 3; i ++ ) {
printf(" %6d %s", Search.bvl[i], MoveIntToStr(Search.bmv[i]).c_str());
}
printf("\n");
fflush ( stdout );
if ( Search.bvl[0] <= - BAN_VALUE || Search.bvl[0] >= BAN_VALUE) {
break;
}
if ( Search.bvl[1] <= - BAN_VALUE || Search.bmv[1] == 0 ) {
break;
}
}
printf ( "totaltime: %.2fs\n", TimeCost(SEARCH_TOTAL_TIME) );
fflush ( stdout );
// 输出最优着法
if ( Search.bmv[0] == 0 || Search.bvl[0] <= - BAN_VALUE ) {
printf ( "bestmove a0a1 resign\n" ); // 认输
fflush ( stdout );
return 0;
}
else {
printf ( "bestmove %s\n", MoveIntToStr(Search.bmv[0]).c_str() );
fflush ( stdout );
return Search.bmv[0];
}
}