Add tt node in case of best score >= alpha

src/search/negamax.rs

@@ -4,7 +4,12 @@ use crate::{
     movegen::r#move::Move,
 };
 
-use super::{move_ordering::score_by_mvv_lva, quiescence::quiescence, transposition_table::{Bound, TTEntry, TranspositionTable}, QUIESCENCE_DEPTH};
+use super::{
+    move_ordering::score_by_mvv_lva,
+    quiescence::quiescence,
+    transposition_table::{Bound, TTEntry, TranspositionTable},
+    QUIESCENCE_DEPTH,
+};
 
 pub fn negamax(
     game: &mut Game,
@@ -99,6 +104,14 @@ pub fn negamax(
             best_move,
             Bound::Upper,
         ));
+    } else {
+        tt.insert(TTEntry::new(
+            game.hash,
+            depth,
+            best_score,
+            best_move,
+            Bound::Exact,
+        ));
     }
 
     (best_move, best_score)