Python：检查两个数组（可能包含重复元素）是否包含相同的元素集

Question

I am trying to solve a homework problem.

Q. Assume the existence of two arrays X and Y of m elements each. Assume that they may possibly contain duplicates (ie, repeated elements), on which a total order relation is defined. a) Develop an efficient algorithm for determining if X and Y contains the same set of elements.

Now, to make this as efficient as possible, someone suggested using Hash tables. I have been trying to implement it.

I have already created the arrays and the hashtable, then I imported one array into the hashtable.

At this point I am looking for the most efficient way to search the array and give me the answer.

dict = {'0':'-','1':'a','2':'b','3':'c'} #declare dictionary

print "first element of dict = ", dict['0']

print "\n"

array1 = ["4","5","6","7","8","9","10"]
print "array 1 = ", array1
array2 = ["4","5","6","7","8","9","10"]
print "array 2 = ", array2

print "\n"

print "array1[3] = ", array1[3]

print "\n"

print "clearing dictionary..."
dict.clear(); 

print "dict = ", dict

print "\n"

x = 0 #iterator for array1

print "importing array1 into dictionary..."

while x < len(array1) :
    dict[x] = array1[x]
    x += 1

print dict

y = 0 #iterator for array2

while y < len(array2) :
    if dict

If someone could kindly guide me further as to the logic I need here, that would be much appreciated.

Answer 1

This is my solution. Is this the most efficient solution? What would be the time complexity? I am guessing O(n). Am I correct?

# define first array
array1 = ["1","1","1","2"]
print "array 1 = ", array1

#define second array
array2 = ["1","2","3"]
print "array 2 = ", array2

#function
def is_empty(x, y):

    #find set difference between first and second array
    difference1 = set(x) - set(y)
    print difference1

    #find set difference between second and first array
    difference2 = set(y) - set(x)
    print difference2

    #union two differences together
    finalset = difference1.union(difference2)
    print finalset

    #if there are elements in finalset, arrays do not contain same set of elements
    if finalset:
        print('The sets do not contain the same set of elements.')
        return False

    #if there are no elements in final set, arrays contain same set of elements
    else:
        print('The sets contain the same set of elements.')
        return True

#function call on two arrays
is_empty(array1, array2)