# Task
 Yesterday you found some shoes in your room. Each shoe is described by two values:
```
type indicates if it's a left or a right shoe;
size is the size of the shoe.
```
 Your task is to check whether it is possible to pair the shoes you found in such a way that each pair consists of a right and a left shoe of an equal size.

# Example

 For:
```
shoes = [[0, 21], 
         [1, 23], 
         [1, 21], 
         [0, 23]]
         ```
the output should be `true;`

 For:
```
shoes = [[0, 21], 
         [1, 23], 
         [1, 21], 
         [1, 23]]
         ```
the output should be `false.`

# Input/Output

 - `[input]` 2D integer array `shoes`

 Array of shoes. Each shoe is given in the format [type, size], where type is either 0 or 1 for left and right respectively, and size is a positive integer.

 Constraints: `2 ≤ shoes.length ≤ 50,  1 ≤ shoes[i][1] ≤ 100.`

 - `[output]` a boolean value

   `true` if it is possible to pair the shoes, `false` otherwise.

Difficulty: EASY
Starter code: def pair_of_shoes(shoes):
	

Solutions:
def pair_of_shoes(a):
	return sorted((s for (lr, s) in a if lr == 1)) == sorted((s for (lr, s) in a if lr == 0))


from collections import defaultdict

def pair_of_shoes(shoes):
	sz = defaultdict(list)
	for i in shoes:
		sz[i[1]].append(i[0])
	return all((i[1].count(1) == i[1].count(0) for i in sz.items()))


from collections import defaultdict

def pair_of_shoes(shoes):
	shoe_counts = defaultdict(int)
	for (shoe_type, shoe_size) in shoes:
		shoe_counts[shoe_size] += 1 if shoe_type else -1
	return all((a == 0 for a in shoe_counts.values()))


from collections import defaultdict

def pair_of_shoes(shoes):
	D = defaultdict(lambda : defaultdict(int))
	for (type, size) in shoes:
		D[size][type] += 1
	return all((v[0] == v[1] for v in D.values()))


pair_of_shoes = lambda s: all([s.count([i[0] ^ 1, i[1]]) == s.count(i) for i in s])


def pair_of_shoes(shoes):
	return not sum((size * (-1) ** side for (side, size) in shoes))


from collections import Counter

def pair_of_shoes(shoes):
	c = Counter()
	for (lr, size) in shoes:
		c[size] += 1 if lr else -1
	return not any(c.values())


def pair_of_shoes(shoes):
	l = [i for (i, j) in shoes]
	m = [j for (i, j) in shoes]
	return sum((m.count(i) % 2 == 0 for i in set(m))) == len(set(m)) and l.count(0) == l.count(1)


from collections import Counter

def pair_of_shoes(shoes):

	def count_of_type(type_):
		return Counter((n for (t, n) in shoes if t == type_))
	return count_of_type(0) == count_of_type(1)


(S, pair_of_shoes) = (lambda a, T: sorted((s for (t, s) in a if t - T)), lambda a: S(a, 0) == S(a, 1))