Daily Coding Problem | Day 849 | Collatz sequence

devstromo · devstromo · commit 3bb5cfced214 · 2024-07-25T23:10:09.000-03:00
diff --git a/daily-coding-problem/src/main/java/com/devstromo/day849/Problem.java b/daily-coding-problem/src/main/java/com/devstromo/day849/Problem.java
@@ -2,7 +2,7 @@
 
 public class Problem {
 
-    public int solve(long n) {
+    public long solve(long n) {
         var iterations = 0;
         while (n > 1) {
             iterations++;
@@ -14,4 +14,14 @@ public int solve(long n) {
         }
         return iterations;
     }
+
+    public long solveRecursive(long n) {
+        if (n == 1) {
+            return 0;
+        }
+        if (n % 2 == 0) {
+            return solveRecursive(n / 2) + 1;
+        }
+        return solveRecursive(3 * n + 1) + 1;
+    }
 }
diff --git a/daily-coding-problem/src/test/java/com/devstromo/day849/ProblemUnitTest.java b/daily-coding-problem/src/test/java/com/devstromo/day849/ProblemUnitTest.java
@@ -21,4 +21,16 @@ public void testSolve(long input, long expected) {
         assertEquals(expected, result, "Expected " + expected + " iterations for input " + input);
     }
 
+    @ParameterizedTest
+    @CsvSource({
+            "8, 3",
+            "3, 7",
+            "1, 0",
+            "27, 111"
+    })
+    public void testSolveRecursive(long input, long expected) {
+        final var result = problem.solveRecursive(input);
+        assertEquals(expected, result, "Expected " + expected + " iterations for input " + input);
+    }
+
 }
