Package g2101_2200.s2103_rings_and_rods

Class Solution

  • public class Solution
extends Object
    2103 - Rings and Rods.

    Easy

    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 denotes the rod that the ith ring 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: 1

    Explanation:

    • The rod labeled 0 holds 3 rings with all colors: red, green, and blue.

    • The rod labeled 6 holds 3 rings, but it only has red and blue.

    • The rod labeled 9 holds only a green ring.

    Thus, the number of rods with all three colors is 1.

    Example 2:

    Input: rings = “B0R0G0R9R0B0G0”

    Output: 1

    Explanation:

    • The rod labeled 0 holds 6 rings with all colors: red, green, and blue.

    • The rod labeled 9 holds only a red ring.

    Thus, the number of rods with all three colors is 1.

    Example 3:

    Input: rings = “G4”

    Output: 0

    Explanation: Only one ring is given. Thus, no rods have all three colors.

    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 ).

    • Constructor Detail

      • Solution

        public Solution()

    • Method Detail

      • countPoints

        public int countPoints​(String rings)