solves rings and rods

Author: anishLearnsToCode

README.md

@@ -498,4 +498,4 @@
 | 2089 | [Find Target Indices After Sorting Array](https://leetcode.com/problems/find-target-indices-after-sorting-array)                                          |                                                       [![Java](assets/java.png)](src/FindTargetIndicesAfterSortingArray.java)                                                        |                                                                                                                                   |
 | 2094 | [Finding 3-Digit Even Numbers](https://leetcode.com/problems/finding-3-digit-even-numbers)                                                                |                                                            [![Java](assets/java.png)](src/Finding3DigitEvenNumbers.java)                                                             |                                                                                                                                   |
 | 2099 | [Find Subsequence of Length K With the Largest Sum](https://leetcode.com/problems/find-subsequence-of-length-k-with-the-largest-sum)                      |                                                    [![Java](assets/java.png)](src/FindSubsequenceOfLengthKWithTheLargestSum.java)                                                    |                                                                                                                                   |
-| 2103 | [Rings and Rods](https://leetcode.com/problems/rings-and-rods)                                                                                            |                                                                                                                                                                                      |                                                                                                                                   |
+| 2103 | [Rings and Rods](https://leetcode.com/problems/rings-and-rods)                                                                                            |                                                                  [![Java](assets/java.png)](src/RingsAndRods.java)                                                                   |                                                                                                                                   |

src/RingsAndRods.java

@@ -0,0 +1,32 @@
+// https://leetcode.com/problems/rings-and-rods
+// T: O(|rings|)
+// S: O(1)
+
+public class RingsAndRods {
+    public int countPoints(String rings) {
+        final boolean[][] rods = new boolean[10][3];
+        for (int i = 0 ; i < rings.length() ; i += 2) {
+            rods[rings.charAt(i + 1) - '0'][toColorIndex(rings.charAt(i))] = true;
+        }
+        int points = 0;
+        for (boolean[] rod : rods) {
+            if (containsAllColors(rod)) {
+                points++;
+            }
+        }
+        return points;
+    }
+
+    private int toColorIndex(char color) {
+        return switch (color) {
+            case 'R' -> 0;
+            case 'G' -> 1;
+            case 'B' -> 2;
+            default -> -1;
+        };
+    }
+
+    private boolean containsAllColors(boolean[] rod) {
+        return rod[0] && rod[1] && rod[2];
+    }
+}