Challenge: Find Symmetric Pairs in a List

Statement

Given a list of pairs, nums, find all the symmetric pairsBy definition, (a, b) and (c, d) are symmetric pairs iff, a = d and b = c. from it. If no symmetric pair is found, return an empty list.

Constraints:

• $2 \leq$ nums.length $\leq10^3$

• nums[i].length $== 2$

• $-10^5\leq$ nums[i][1] $\leq 10^5$

• $-10^5\leq$ nums[i][2] $\leq10^5$

Examples