1 files changed, 22 insertions, 24 deletions

diff --git a/include/negamax.c b/include/negamax.c
index 16eba9a..43fa5f6 100644
--- a/include/negamax.c
+++ b/include/negamax.c
@@ -102,7 +102,7 @@ negamax_generate(void) {
 	tt_init();
 	float result = negamax(negamax_search_depth,
 												 -safe_infty, safe_infty,
-												 (ply&1)?1.0:-1.0);
+												 (ply & 1) ? +1.0 : -1.0);
 	tt_free();
 
 	return result;
@@ -113,49 +113,47 @@ static enum WIN_TYPE w;
 static float
 negamax(const uint8_t cur_depth, float alpha, float beta,
 				const float colour) {
+
+	if (cur_depth == 0) return colour*cnn1986_evaluate_black_win();
+
 	float value = -infty;
 
 	action_list_t *list = action_list_generate();
+	if (list == NULL) return value; // ???
 
-	for (action_list_t *node=list; node!=NULL; node=node->next) {
-		negamax_display_progress(cur_depth);
-
+	for (action_node_t *node=list->head; node!=NULL; node=node->next) {
 		action_take(node);
 
 		// Somebody won?
-		if (ply >= 2*board_size - 3 && (w = check_win()) < 0xFF) {
-			if (w == WIN_ROAD_BLACK || w == WIN_FLAT_BLACK) {
-				value = colour*infty;
-				if (value > 0) {
-					// Always take the win for ourselves
-					action_undo(node);
-					if (cur_depth == negamax_search_depth)
-						action_to_ptn(node, negamax_ptn);
-					goto prune;
-				}
-			} else if (w == WIN_DRAW) value = 0; // Draw is fixed at neutral
+		if (ply >= 2*board_size - 2 && (w = check_win()) < 0xFF) {
+			if (w == WIN_ROAD_BLACK || w == WIN_FLAT_BLACK) value = colour*infty;
+			else if (w == WIN_DRAW) value = 0; // Draw is fixed at neutral
 			else value = -colour*infty;
-		} else if (cur_depth > 1) {
-			// Recurse away from the leaves
-			value = fmax(value, -negamax(cur_depth - 1, -beta, -alpha, -colour));
+			if (value > 0) {
+				// Always take the win for ourselves
+				action_undo(node);
+				if (cur_depth == negamax_search_depth) {
+					action_to_ptn(node, negamax_ptn);
+				}
+				goto prune;
+			}
 		} else {
-			// Evaluate a leaf
-			value = fmax(value, colour * cnn1986_evaluate_black_win());
+			value = fmax(value, -negamax(cur_depth - 1, -beta, -alpha, -colour));
 		}
 
 		action_undo(node);
 
+		negamax_display_progress(cur_depth, list->length);
+
 		if (value > alpha) {
 			alpha = value;
 			if (cur_depth == negamax_search_depth)
 				action_to_ptn(node, negamax_ptn);
+			if (alpha >= beta) break;
 		}
-		if (alpha >= beta) break;
 	}
-
-	action_list_free(list);
-
  prune:
+	action_list_free(list);
 	return value;
 }