List-2 directory added

Author: akiltipu

List-2/big_diff.py

@@ -0,0 +1,11 @@
+# Given an array length 1 or more of ints, 
+# return the difference between the largest and smallest values in the array. 
+# Note: the built-in min(v1, v2) and max(v1, v2) functions return the smaller or larger of two values.
+
+
+# big_diff([10, 3, 5, 6]) → 7
+# big_diff([7, 2, 10, 9]) → 8
+# big_diff([2, 10, 7, 2]) → 8
+
+def big_diff(nums):
+    return max(nums) - min(nums)

List-2/centered_average.py

@@ -0,0 +1,16 @@
+# 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):
+    nums.sort()
+    li = nums[1:-1]
+    return sum(li)//len(li)

List-2/count_evens.py

@@ -0,0 +1,14 @@
+# Return the number of even ints in the given array. 
+# Note: the % "mod" operator computes the remainder, e.g. 5 % 2 is 1.
+
+
+# count_evens([2, 1, 2, 3, 4]) → 3
+# count_evens([2, 2, 0]) → 3
+# count_evens([1, 3, 5]) → 0
+
+def count_evens(nums):
+    sum = 0
+    for i in nums:
+        if i % 2 == 0:
+            sum += 1
+    return sum

List-2/has22.py

@@ -0,0 +1,13 @@
+# 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):
+    for i in range(len(nums)-1):
+        if nums[i] == 2 and nums[i+1] == 2:
+            return True
+    return False

List-2/sum13.py

@@ -0,0 +1,19 @@
+# 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 += 1
+        else:
+            total += nums[i]
+        i += 1
+    return total

List-2/sum67.py

@@ -0,0 +1,21 @@
+# 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):
+    total = 0
+    is6 = False
+  
+    for i in range(len(nums)):
+        if nums[i] == 6:
+            is6 = True
+        if not is6:
+            total += nums[i]
+        if nums[i] == 7 and is6:
+            is6 = False
+    return total