Leetcode 2103: Rings and Rods

In this problem, we are given a list of rings going into rods, and we should return how many rods have rings with all the possible colors.

There are n rings and each ring is either red, green, or blue. The rings are distributed across ten rods labeled from 0 to 9.
You are given a string rings of length 2n that describes the n rings that are placed onto the rods. Every two characters in rings forms a color-position pair that is used to describe each ring where:
The first character of the ith pair denotes the ith ring's color ('R', 'G', 'B').
The second character of the ith pair…