##### Short Problem Definition:

Given a list of unsorted integers, A={a1,a2,…,aN}, can you find the pair of elements that have the smallest absolute difference between them? If there are multiple pairs, find them all.

##### Link

##### Complexity:

time complexity is `O(n\*log(n)) // sorting`

space complexity is `O(n)`

##### Execution:

Just sort the array and print the smallest difference.

##### Solution:

```
#!/usr/bin/py
from sys import maxint
def closest(a):
a.sort()
smallest_difference = maxint
smallest_pairs = []
for idx in xrange(len(a)-1):
diff = a[idx+1] - a[idx]
if diff < smallest_difference:
smallest_difference = diff
smallest_pairs = [(a[idx], a[idx+1])]
elif diff == smallest_difference:
smallest_pairs.append((a[idx], a[idx+1]))
for pair in smallest_pairs:
print pair[0], pair[1],
if __name__ == '__main__':
n = input()
vec = map(int, raw_input().split())
closest(vec)
```