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First solution in Clear category for Swap Nodes by Wienands
def swap_nodes(a):
if a==[]:
return []
res=[]
for i in range(0,len(a)-1,2):
res.extend([a[i+1],a[i]])
if len(a)%2 != 0:
res.append(a[-1])
return res
if __name__ == '__main__':
print("Example:")
print(list(swap_nodes([1, 2, 3, 4])))
# These "asserts" are used for self-checking and not for an auto-testing
assert list(swap_nodes([1, 2, 3, 4])) == [2, 1, 4, 3]
assert list(swap_nodes([5, 5, 5, 5])) == [5, 5, 5, 5]
assert list(swap_nodes([1, 2, 3])) == [2, 1, 3]
assert list(swap_nodes([3])) == [3]
assert list(swap_nodes(["hello", "world"])) == ["world", "hello"]
print("Coding complete? Click 'Check' to earn cool rewards!")
April 16, 2019