From 8435003362f30b2bba7a71ff3be44bdf025b76af Mon Sep 17 00:00:00 2001
From: Vahagn Khachatryan <vahagn.khachatryan@gmail.com>
Date: Sun, 28 May 2017 23:57:44 +0100
Subject: [PATCH] Print indices of max element of the array randomly+evenly.

---
 .../interviews/training/print_max_evenly.py   | 41 +++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 puzzles/interviews/training/print_max_evenly.py

diff --git a/puzzles/interviews/training/print_max_evenly.py b/puzzles/interviews/training/print_max_evenly.py
new file mode 100644
index 0000000..3afbb36
--- /dev/null
+++ b/puzzles/interviews/training/print_max_evenly.py
@@ -0,0 +1,41 @@
+import random
+
+
+#
+# You have a array with integers: e.g. [ 1, -2, 0, 6, 2, -4, 6, 6 ]
+# You need to write a function which will evenly return indexes of a
+# max value in the array.
+# In the example above max value is 6, and its positions are 3, 6 and 7.
+# So each run function should return random index from the set.
+#
+# Try to implement with O(n) for computation and memory.
+# Try to reduce memory complexity to O(1).
+#
+def return_max_evenly(arr):
+    mv = float('-inf')
+    mi = -1
+    mc = 0
+    for i in range(len(arr)):
+        if mv < arr[i]:
+            mv = arr[i]
+            mi = i
+            mc = 1
+        elif mv == arr[i]:
+            mc = mc + 1
+            if random.random() < 1./mc:
+                mi = i
+    if mi != -1:
+        return mi
+
+
+if __name__ == "__main__":
+    random.seed()
+    arr = [1, -2, 0, 6, 2, -4, 6, 6]
+    ret = {}
+    for i in range(10000):
+        r = return_max_evenly(arr)
+        if r in ret:
+            ret[r] = ret[r] + 1
+        else:
+            ret[r] = 1
+    print(ret)