Three Five Multiples

ardallie · ardallie · commit 356a4a417672 · 2021-08-17T02:43:01.000+01:00
diff --git a/src/medium/ThreeFiveMultiples.java b/src/medium/ThreeFiveMultiples.java
@@ -0,0 +1,60 @@
+package medium;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * Have the function ThreeFiveMultiples(num) return the sum
+ * of all the multiples of 3 and 5 that are below num.
+ * For example: if num is 10, the multiples of 3 and 5
+ * that are below 10 are 3, 5, 6, and 9,
+ * and adding them up you get 23, so your program should return 23.
+ * The integer being passed will be between 1 and 100.
+ */
+public class ThreeFiveMultiples {
+
+  private static final Set<Integer> freq = new HashSet<>();
+
+  /**
+   * Count Multiples.
+   *
+   * @param num input number
+   * @param mp  a factor (multiplier)
+   */
+  private static void countMultiples(int num, int mp) {
+    for (int i = mp; i < num; i += mp) {
+      if (i % mp == 0) {
+        freq.add(i);
+      }
+    }
+  }
+
+  /**
+   * Three Five Multiples function.
+   *
+   * @param num input number
+   * @return a result
+   */
+  private static int threeFiveMultiples(int num) {
+    int total = 0;
+    countMultiples(num, 3);
+    countMultiples(num, 5);
+    for (int i : freq) {
+      total += i;
+    }
+    return total;
+  }
+
+  /**
+   * Entry point.
+   *
+   * @param args command line arguments
+   */
+  public static void main(String[] args) {
+    var result1 = threeFiveMultiples(17);
+    System.out.println(result1);
+    var result2 = threeFiveMultiples(117);
+    System.out.println(result2);
+  }
+
+}
