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All runs / f98c26fcec2e

merge_intervals gives wrong results

Done

/home/devdi/devswarm/evals/tasks/merge_intervals/repo · 2026-11-09 16:17:57 UTC · took 30.4s

  1. Plan (done)
  2. Code (done)
  3. Test (done)
  4. Review (done)
  5. Finish (done)
Cost
$0.0035
Tests
Passed
Iterations
1
Re-plans
0
LLM calls
10
Prompt read from cache
75%

Usage by agent

Cost per agent
planner: $0.0008 planner planner, Cost: $0.0008 $0.0008 coder: $0.0008 coder coder, Cost: $0.0008 $0.0008 tester: $0.0012 tester tester, Cost: $0.0012 $0.0012 reviewer: $0.0006 reviewer reviewer, Cost: $0.0006 $0.0006
Tokens per agent
  • Cache read
  • Cache write
  • Input
  • Output
planner: 8,009 planner planner, Cache read: 5,802 planner, Cache write: 944 planner, Output: 1,255 8,009 coder: 12.4K coder coder, Cache read: 9,166 coder, Cache write: 2,234 coder, Output: 953 12.4K tester: 15.5K tester tester, Cache read: 10.7K tester, Cache write: 3,389 tester, Output: 1,427 15.5K reviewer: 4,698 reviewer reviewer, Cache read: 1,727 reviewer, Cache write: 2,304 reviewer, Output: 663 4,698
View as table
AgentCostCache readCache writeInputOutput
planner$0.00085,80294481,255
coder$0.00089,1662,2348953
tester$0.001210,6663,38981,427
reviewer$0.00061,7272,3044663

Timeline

  1. planner iteration 1 Finished 3 calls · 8,009 tokens · $0.0008 · 7.6s

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  2. coder iteration 1 Finished 3 calls · 12.4K tokens · $0.0008 · 5.8s

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  3. tester iteration 1 Finished 3 calls · 15.5K tokens · $0.0012 · 11.3s

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  4. verify iteration 1 Passed 0.6s 
    ..............                                                           [100%]
14 passed in 0.03s
  5. reviewer iteration 1 Finished 1 calls · 4,698 tokens · $0.0006 · 4.4s

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Final diff

diff --git a/intervals.py b/intervals.py
index 76e6d7f..2bafff4 100644
--- a/intervals.py
+++ b/intervals.py
@@ -1,8 +1,8 @@
 def merge_intervals(intervals: list[tuple[int, int]]) -> list[tuple[int, int]]:
     merged: list[tuple[int, int]] = []
-    for start, end in intervals:
-        if merged and start < merged[-1][1]:
-            merged[-1] = (merged[-1][0], end)
+    for start, end in sorted(intervals):
+        if merged and start <= merged[-1][1]:
+            merged[-1] = (merged[-1][0], max(merged[-1][1], end))
         else:
             merged.append((start, end))
     return merged
diff --git a/test_intervals.py b/test_intervals.py
index 1e6a250..fa32ed3 100644
--- a/test_intervals.py
+++ b/test_intervals.py
@@ -7,3 +7,53 @@ def test_overlap():
 
 def test_separate():
     assert merge_intervals([(1, 2), (3, 4)]) == [(1, 2), (3, 4)]
+
+
+def test_touching():
+    assert merge_intervals([(1, 2), (2, 3)]) == [(1, 3)]
+
+
+def test_unsorted():
+    assert merge_intervals([(5, 6), (1, 2)]) == [(1, 2), (5, 6)]
+
+
+def test_containment():
+    assert merge_intervals([(1, 10), (2, 3)]) == [(1, 10)]
+
+
+def test_empty():
+    assert merge_intervals([]) == []
+
+
+def test_single():
+    assert merge_intervals([(1, 2)]) == [(1, 2)]
+
+
+def test_unsorted_containment():
+    assert merge_intervals([(2, 3), (1, 10)]) == [(1, 10)]
+
+
+def test_chain_of_touching():
+    assert merge_intervals([(3, 4), (1, 2), (2, 3)]) == [(1, 4)]
+
+
+def test_duplicates():
+    assert merge_intervals([(1, 2), (1, 2)]) == [(1, 2)]
+
+
+def test_contained_then_extended():
+    assert merge_intervals([(1, 5), (2, 3), (4, 8)]) == [(1, 8)]
+
+
+def test_point_touching_end():
+    assert merge_intervals([(1, 2), (2, 2)]) == [(1, 2)]
+
+
+def test_point_separate_unsorted():
+    assert merge_intervals([(3, 3), (1, 2)]) == [(1, 2), (3, 3)]
+
+
+def test_input_not_mutated():
+    data = [(5, 6), (1, 2)]
+    merge_intervals(data)
+    assert data == [(5, 6), (1, 2)]