Fix serialization

vm/src/air_private_input.rs

@@ -126,6 +126,8 @@ pub struct ModInputInstance {
     pub values_ptr: usize,
     pub offsets_ptr: usize,
     pub n: usize,
+    #[serde(deserialize_with = "mod_input_instance_batch_serde::deserialize")]
+    #[serde(serialize_with = "mod_input_instance_batch_serde::serialize")]
     pub batch: BTreeMap<usize, ModInputMemoryVars>,
 }
 
@@ -205,6 +207,29 @@ impl AirPrivateInputSerializable {
     }
 }
 
+mod mod_input_instance_batch_serde {
+    use super::*;
+
+    use serde::{Deserializer, Serializer};
+
+    pub(crate) fn serialize<S: Serializer>(
+        value: &BTreeMap<usize, ModInputMemoryVars>,
+        s: S,
+    ) -> Result<S::Ok, S::Error> {
+        let value = value.iter().map(|v| v.1).collect::<Vec<_>>();
+
+        value.serialize(s)
+    }
+
+    pub(crate) fn deserialize<'de, D: Deserializer<'de>>(
+        d: D,
+    ) -> Result<BTreeMap<usize, ModInputMemoryVars>, D::Error> {
+        let value = Vec::<ModInputMemoryVars>::deserialize(d)?;
+
+        Ok(value.into_iter().enumerate().collect())
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::types::layout_name::LayoutName;