List-2 Solutions

Author: rokas2019

List-2/centered_average.py

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+# Return the "centered" average of an array of ints, which we'll say is the mean average of the values,
+# except ignoring the largest and smallest values in the array. If there are multiple copies of the smallest value,
+# ignore just one copy, and likewise for the largest value. Use int division to produce the final average. You may
+# assume that the array is length 3 or more.
+#
+#
+# centered_average([1, 2, 3, 4, 100]) → 3
+# centered_average([1, 1, 5, 5, 10, 8, 7]) → 5
+# centered_average([-10, -4, -2, -4, -2, 0]) → -3
+
+def centered_average(nums):
+    return (sum(nums) - min(nums) - max(nums)) / (len(nums) - 2)
+
+
+print(centered_average([1, 1, 5, 5, 10, 8, 7]))

List-2/has22.py

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+# Given an array of ints, return True if the array contains a 2 next to a 2 somewhere.
+#
+#
+# has22([1, 2, 2]) → True
+# has22([1, 2, 1, 2]) → False
+# has22([2, 1, 2]) → False
+
+
+def has22(nums):
+    i = 0
+    while i < len(nums)-1:
+        if nums[i] == 2 and nums[i + 1] == 2:
+            return True
+        i += 1
+    return False
+

List-2/sum13.py

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+# Return the sum of the numbers in the array, returning 0 for an empty array. Except the number 13 is very unlucky,
+# so it does not count and numbers that come immediately after a 13 also do not count.
+#
+#
+# sum13([1, 2, 2, 1]) → 6
+# sum13([1, 1]) → 2
+# sum13([1, 2, 2, 1, 13]) → 6
+
+
+def sum13(nums):
+    total = 0
+    i = 0
+    while i < len(nums):
+        if nums[i] == 13:
+            i += 2
+            continue
+        total += nums[i]
+        i += 1
+    return total
+

List-2/sum67.py

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+# Return the sum of the numbers in the array, except ignore sections of numbers starting with a 6 and extending to
+# the next 7 (every 6 will be followed by at least one 7). Return 0 for no numbers.
+#
+#
+# sum67([1, 2, 2]) → 5
+# sum67([1, 2, 2, 6, 99, 99, 7]) → 5
+# sum67([1, 1, 6, 7, 2]) → 4
+
+def sum67(nums):
+    indicator = True
+    total = 0
+    for i in nums:
+        if i == 6:
+            indicator = False
+        if indicator:
+            total += i
+            continue
+        if i == 7:
+            indicator = True
+    return total