From d6738d1eaf4ee1d6403851cf79cdf6ce694e30b9 Mon Sep 17 00:00:00 2001
From: mjalalzai <33738574+MForensic@users.noreply.github.com>
Date: Tue, 17 Oct 2023 11:48:35 -0700
Subject: [PATCH] Merging committees

---
 carnot/carnot-vote-aggregation.py |  2 +-
 carnot/merging_committees.py      | 29 +++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 1 deletion(-)
 create mode 100644 carnot/merging_committees.py

diff --git a/carnot/carnot-vote-aggregation.py b/carnot/carnot-vote-aggregation.py
index 945956d..2f9874e 100644
--- a/carnot/carnot-vote-aggregation.py
+++ b/carnot/carnot-vote-aggregation.py
@@ -401,7 +401,7 @@ class Carnot:
             # Forward the vote to the parent committee
             return Send(to=self.overlay.parent_committee, payload=vote)
 
-# ToDo: Is not needed anymore
+
     def forward_timeout_qc(self, msg: TimeoutQc) -> Optional[Event]:
         # Assertions for input validation
         assert msg.view == self.current_view, "Received TimeoutQc with correct view"
diff --git a/carnot/merging_committees.py b/carnot/merging_committees.py
new file mode 100644
index 0000000..b6334d2
--- /dev/null
+++ b/carnot/merging_committees.py
@@ -0,0 +1,29 @@
+def merge_committees(committees):
+    num_committees = len(committees)
+    merged_committees = []
+
+    # Sort the committees by size
+    sorted_committees = sorted(committees, key=len)
+
+    # Divide the committees into two groups: smaller and larger
+    smaller_committees = sorted_committees[:num_committees // 2]
+    larger_committees = sorted_committees[num_committees // 2:]
+
+    # Merge smaller and larger committees pairwise
+    for smaller, larger in zip(smaller_committees, larger_committees):
+        merged_committee = set(smaller)
+        merged_committee.update(larger)
+        merged_committees.append(merged_committee)
+
+    # Handle the leftover committee, if it exists
+    if num_committees % 2 == 1:
+        leftover_committee = set(sorted_committees[-1])
+        num_merged_committees = len(merged_committees)
+
+        # Distribute leftover members evenly among merged committees
+        for member in leftover_committee:
+            # Find the index of the merged committee with the smallest size
+            smallest_idx = min(range(num_merged_committees), key=lambda i: len(merged_committees[i]))
+            merged_committees[smallest_idx].add(member)
+
+    return merged_committees
\ No newline at end of file