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authorVincent Ambo <mail@tazj.in>2021-12-13T22·51+0300
committerVincent Ambo <mail@tazj.in>2021-12-13T23·15+0300
commit019f8fd2113df4c5247c3969c60fd4f0e08f91f7 (patch)
tree76a857f61aa88f62a30e854651e8439db77fd0ea /users/wpcarro/scratch/facebook/find-rotation-point.py
parent464bbcb15c09813172c79820bcf526bb10cf4208 (diff)
parent6123e976928ca3d8d93f0b2006b10b5f659eb74d (diff)
subtree(users/wpcarro): docking briefcase at '24f5a642' r/3226
git-subtree-dir: users/wpcarro
git-subtree-mainline: 464bbcb15c09813172c79820bcf526bb10cf4208
git-subtree-split: 24f5a642af3aa1627bbff977f0a101907a02c69f
Change-Id: I6105b3762b79126b3488359c95978cadb3efa789
Diffstat (limited to 'users/wpcarro/scratch/facebook/find-rotation-point.py')
-rw-r--r--users/wpcarro/scratch/facebook/find-rotation-point.py47
1 files changed, 47 insertions, 0 deletions
diff --git a/users/wpcarro/scratch/facebook/find-rotation-point.py b/users/wpcarro/scratch/facebook/find-rotation-point.py
new file mode 100644
index 000000000000..3636be4d93b5
--- /dev/null
+++ b/users/wpcarro/scratch/facebook/find-rotation-point.py
@@ -0,0 +1,47 @@
+from math import floor
+
+def find_rotation(xs):
+    if xs[0] < xs[-1]:
+        return xs[0]
+    beg, end = 0, len(xs) - 1
+    found = False
+    count = 10
+    while not found and count >= 0:
+        i = beg + floor((end - beg) / 2)
+        if xs[beg] < xs[i]:
+            beg = i
+            i = beg + floor((end - beg) / 2)
+        elif xs[beg] > xs[i]:
+            end = i
+        found = xs[i - 1] > xs[i]
+        count -= 1
+    return xs[i]
+
+
+xs = [(['ptolemaic',
+        'retrograde',
+        'supplant',
+        'undulate',
+        'xenoepist',
+        'zebra',
+        'asymptote',
+        'babka',
+        'banoffee',
+        'engender',
+        'karpatka',
+        'othellolagkage',
+        ], "asymptote"),
+      (['asymptote',
+        'babka',
+        'banoffee',
+        'engender',
+        'karpatka',
+        'othellolagkage',
+        ], "asymptote"),
+      ]
+
+for x, expected in xs:
+    result = find_rotation(x)
+    print(x, result)
+    assert result == expected
+    print("Success!")