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Task/Averages-Mode/Java/averages-mode.java

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+import java.util.*;
+
+public class Mode {
+    public static <T> List<T> mode(List<? extends T> coll) {
+        Map<T, Integer> seen = new HashMap<T, Integer>();
+        int max = 0;
+        List<T> maxElems = new ArrayList<T>();
+        for (T value : coll) {
+            if (seen.containsKey(value))
+                seen.put(value, seen.get(value) + 1);
+            else
+                seen.put(value, 1);
+            if (seen.get(value) > max) {
+                max = seen.get(value);
+                maxElems.clear();
+                maxElems.add(value);
+            } else if (seen.get(value) == max) {
+                maxElems.add(value);
+            }
+        }
+        return maxElems;
+    }
+
+    public static void main(String[] args) {
+        System.out.println(mode(Arrays.asList(1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17))); // prints [6]
+        System.out.println(mode(Arrays.asList(1, 1, 2, 4, 4))); // prints [1, 4]
+    }
+}