Rings and Rods
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
i^thpair denotes thei^thring's color ('R','G','B'). - The second character of the
i^thpair denotes the rod that thei^thring is placed on ('0'to'9').
For example, "R3G2B1" describes n == 3 rings: a red ring placed onto the rod labeled 3, a green ring placed onto the rod labeled 2, and a blue ring placed onto the rod labeled 1.
Return the number of rods that have all three colors of rings on them.
Example 1
Input
rings = "B0B6G0R6R0R6G9"Output
1The rod labeled 0 has red, green, and blue rings, while rods 6 and 9 do not have all three colors.
Example 2
Input
rings = "B0R0G0R9R0B0G0"Output
1The rod labeled 0 has red, green, and blue rings, while rod 9 has only a red ring.
Constraints
- rings.length == 2 * n
- 1 <= n <= 100
- rings[i] where i is even is either 'R', 'G', or 'B' (0-indexed).
- rings[i] where i is odd is a digit from '0' to '9' (0-indexed).