fix othello player skip logic

src/complexagent.rs

@@ -226,9 +226,9 @@ impl FutureMoves {
         let mut new_arena = Vec::new();
         let mut index_map = vec![None; self.arena.len()];
 
-        for (old_idx, _) in retain.iter().enumerate().filter(|(_, a)| **a) {
+        for (old_idx, _) in retain.iter().enumerate().rev().filter(|(_, a)| **a) {
             index_map[old_idx] = Some(new_arena.len());
-            let mut node = self.arena[old_idx].clone();
+            let mut node = self.arena.remove(old_idx);
             node.parent = node.parent.and_then(|p| index_map[p]);
             node.children = node.children.iter().filter_map(|&c| index_map[c]).collect();
             new_arena.push(node);