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<sup>th</sup> pair denotes the i<sup>th</sup> ring's color ('R', 'G', 'B').

• The second character of the i<sup>th</sup> pair denotes the rod that the i<sup>th</sup> 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.

LeetCode Problem - 2103

class Solution {
    public int countPoints(String rings) {
        int answer = 0; // Initialize the answer counter

        // Iterate over numbers 0-9 (as characters)
        for(int i=0; i<10; i++){
            boolean red = false;
            boolean green = false;
            boolean blue = false;
            char flag = (char) (i + '0'); // Convert integer to character ('0'-'9')

            // Iterate through the rings string
            for(int j=0; j<rings.length(); j++){
                char c = rings.charAt(j); // Get the current character in the rings string
                if(flag == c){ // Check if the current character matches the current number (0-9)
                    char color = rings.charAt(j-1); // Get the color before the current character
                    // Set corresponding color flag to true based on the color before the number
                    if(color == 'R'){
                        red = true;
                    } else if(color == 'B'){
                        blue = true;
                    } else if (color == 'G'){
                        green = true;
                    }
                }
                // If all three colors are found (red, green, blue), increment answer and break the loop
                if(red && blue && green){
                    answer++;
                    break;
                }
            }
        }
        return answer; // Return the total number of points counted
    }
}