TheAlgorithms · gashev · Apr 24, 2021
diff --git a/ProjectEuler/Problem14.java b/ProjectEuler/Problem14.java
@@ -0,0 +1,58 @@
+package ProjectEuler;
+/**
+ * The following iterative sequence is defined for the set of positive 
+ * integers:
+ *
+ * <p>n → n/2 (n is even)
+ * <p>n → 3n + 1 (n is odd)
+ *
+ * <p>Using the rule above and starting with 13, we generate the following 
+ * sequence:
+ * 
+ * <p>13 → 40 → 20 → 10 → 5 → 16 → 8 → 4 → 2 → 1
+ *
+ * <p>It can be seen that this sequence (starting at 13 and finishing at 1)
+ * contains 10 terms. Although it has not been proved yet (Collatz Problem), 
+ * it is thought that all starting numbers finish at 1.
+ *
+ * <p>Which starting number, under one million, produces the longest chain?
+ * 
+ * <p>NOTE: Once the chain starts the terms are allowed to go above one
+ * million.
+ */
+public class Problem14 {
+  public static void main(String[] args) {
+    assert solution1(1000000) == 837799;
+  }
+
+  static int getSequenceLength(long num) {
+    int length = 1;
+
+    while (num > 1) {
+      if (num % 2 == 0) {
+        num = num / 2;
+      } else {
+        num = 3 * num + 1;
+      }
+      length++;
+    }
+
+    return length;
+  }
+
+  public static int solution1(int maxNumber) {
+    int maxLength = 0;
+    int num = 0;
+    int len;
+
+    for (int i = 1; i <= maxNumber; i++) {
+      len = getSequenceLength(i);
+      if (len > maxLength) {
+        maxLength = len;
+        num = i;
+      }
+    }
+
+    return num;
+  }
+}