List-1 directory added

Author: akiltipu

List-1/common_end.py

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+# Given 2 arrays of ints, a and b, 
+# return True if they have the same first element or they have the same last element. 
+# Both arrays will be length 1 or more.
+
+
+# common_end([1, 2, 3], [7, 3]) → True
+# common_end([1, 2, 3], [7, 3, 2]) → False
+# common_end([1, 2, 3], [1, 3]) → True
+
+def common_end(a, b):
+    return (len(a) and len(b) >= 1 and a == b or a[0] == b[0] or a[-1] == b[-1])

List-1/first_last6.py

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+# Given an array of ints, 
+# return True if 6 appears as either the first or last element in the array. 
+# The array will be length 1 or more.
+
+
+# first_last6([1, 2, 6]) → True
+# first_last6([6, 1, 2, 3]) → True
+# first_last6([13, 6, 1, 2, 3]) → False
+
+def first_last6(nums):
+    return(nums[0] == 6 or nums[-1] == 6)

List-1/has23.py

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+# Given an int array length 2, 
+# return True if it contains a 2 or a 3.
+
+
+# has23([2, 5]) → True
+# has23([4, 3]) → True
+# has23([4, 5]) → False
+
+def has23(nums):
+    return 2 == nums[0] or 2 == nums[1] or 3 == nums[0] or 3 == nums[1]

List-1/make_ends.py

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+# Given an array of ints, 
+# return a new array length 2 containing the first and last elements from the original array. 
+# The original array will be length 1 or more.
+
+
+# make_ends([1, 2, 3]) → [1, 3]
+# make_ends([1, 2, 3, 4]) → [1, 4]
+# make_ends([7, 4, 6, 2]) → [7, 2]
+
+def make_ends(nums):
+    return [nums[0], nums[-1]]

List-1/make_pi.py

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+# Return an int array length 3 containing the first 3 digits of pi, {3, 1, 4}.
+
+
+# make_pi() → [3, 1, 4]
+
+def make_pi():
+    return [3, 1, 4]

List-1/max_end3.py

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+# Given an array of ints length 3, 
+# figure out which is larger, 
+# the first or last element in the array, 
+# and set all the other elements to be that value. 
+# Return the changed array.
+
+
+# max_end3([1, 2, 3]) → [3, 3, 3]
+# max_end3([11, 5, 9]) → [11, 11, 11]
+# max_end3([2, 11, 3]) → [3, 3, 3]
+
+
+def max_end3(nums):
+    if nums[0] > nums[2]:
+        return [nums[0], nums[0], nums[0]]
+    else:
+        return [nums[2], nums[2], nums[2]]

List-1/middle_way.py

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+# Given 2 int arrays, a and b, each length 3, 
+# return a new array length 2 containing their middle elements.
+
+
+# middle_way([1, 2, 3], [4, 5, 6]) → [2, 5]
+# middle_way([7, 7, 7], [3, 8, 0]) → [7, 8]
+# middle_way([5, 2, 9], [1, 4, 5]) → [2, 4]
+
+def middle_way(a, b):
+    return [a[1], b[1]]

List-1/reverse3.py

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+# Given an array of ints length 3, 
+# return a new array with the elements in reverse order, 
+# so {1, 2, 3} becomes {3, 2, 1}.
+
+
+# reverse3([1, 2, 3]) → [3, 2, 1]
+# reverse3([5, 11, 9]) → [9, 11, 5]
+# reverse3([7, 0, 0]) → [0, 0, 7]
+
+def reverse3(nums):
+    return [nums[2], nums[1], nums[0]]

List-1/rotate_left3.py

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+# Given an array of ints length 3, 
+# return an array with the elements "rotated left" 
+# so {1, 2, 3} yields {2, 3, 1}.
+
+
+# rotate_left3([1, 2, 3]) → [2, 3, 1]
+# rotate_left3([5, 11, 9]) → [11, 9, 5]
+# rotate_left3([7, 0, 0]) → [0, 0, 7]
+
+def rotate_left3(nums):
+    return [nums[1], nums[2], nums[0]]

List-1/same_first_last.py

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+# Given an array of ints, 
+# return True if the array is length 1 or more, 
+# and the first element and the last element are equal.
+
+
+# same_first_last([1, 2, 3]) → False
+# same_first_last([1, 2, 3, 1]) → True
+# same_first_last([1, 2, 1]) → True
+
+ 
+def same_first_last(nums):
+    return (len(nums) >= 1 and nums[0] == nums[-1])
+
+
+#def same_first_last(nums):
+#  if len(nums) >= 1:
+#    return (nums[0] == nums[-1])
+#  else:
+#    return False

List-1/sum2.py

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+# Given an array of ints, 
+# return the sum of the first 2 elements in the array. 
+# If the array length is less than 2, 
+# just sum up the elements that exist, 
+# returning 0 if the array is length 0.
+
+
+# sum2([1, 2, 3]) → 3
+# sum2([1, 1]) → 2
+# sum2([1, 1, 1, 1]) → 2
+
+def sum2(nums):
+    if len(nums) < 2:
+        return sum(nums)
+    else:
+        return nums[0]+nums[1]

List-1/sum3.py

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+# Given an array of ints length 3, 
+# return the sum of all the elements.
+
+
+# sum3([1, 2, 3]) → 6
+# sum3([5, 11, 2]) → 18
+# sum3([7, 0, 0]) → 7
+
+def sum3(nums):
+    return (nums[0] + nums[1] + nums[2])
+    #return sum(nums)