Fix winning condition for racing kings (close #9)

Correctly evaluate positions where both kings are on the back rank.

racingkings STC
LLR: 2.95 (-2.94,2.94) [-10.00,5.00]
Total: 354 W: 144 L: 95 D: 115
http://35.161.250.236:6543/tests/view/5be9cb8e6e23db7639060c7d

racingkings LTC
LLR: 2.97 (-2.94,2.94) [-10.00,5.00]
Total: 273 W: 110 L: 62 D: 101
http://35.161.250.236:6543/tests/view/5bea06106e23db7639060c80

diff --git a/src/position.h b/src/position.h
index a993671..2c621b5 100644 (file)
--- a/src/position.h
+++ b/src/position.h
@@ -557,7 +557,8 @@ inline bool Position::is_variant_end(Value& result, int ply) const {
       && flag_move()
       && (capture_the_flag(sideToMove) & pieces(sideToMove, capture_the_flag_piece())))
   {
-      result = mate_in(ply);
+      result =  (capture_the_flag(~sideToMove) & pieces(~sideToMove, capture_the_flag_piece()))
+              && sideToMove == WHITE ? VALUE_DRAW : mate_in(ply);
       return true;
   }
   // nCheck