feb 2015 problem 8 MMM

uil/aplus-february-2015/7/MMM.java

@@ -0,0 +1,72 @@
+import static java.lang.System.out;
+import java.util.Scanner;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Collections;
+import java.io.File;
+import java.io.IOException;
+
+class Main {
+    public static void main(String[] args) throws IOException {
+        Scanner s = new Scanner(new File("mmm.dat"));
+        while(s.hasNextLine()) {
+            String line = s.nextLine();
+            Scanner r = new Scanner(line);
+            int i = 0;
+            while(r.hasNextDouble()) {
+                i++;
+                r.nextDouble();
+            }
+            double[] arr = new double[i];
+            r = new Scanner(line);
+            i = 0;
+            while(r.hasNextDouble())
+                arr[i++] = r.nextDouble();
+            out.println(String.format("%.2f %.2f %.2f %.2f", mean(arr), median(arr), mode(arr), mmm(arr)));
+        }
+    }
+
+    public static double mean(double[] values) {
+        double sum = 0;
+        for(double value : values)
+            sum += value;
+        return sum / values.length;
+    }
+
+    // 1 2 3 4 5 6
+    //     ^ ^ mid = (7/2) - 1
+    //     med = ([mid]+[mid+1]) / 2
+    public static double median(double[] values) {
+        Arrays.sort(values);
+        int center = values.length / 2 - 1;
+        if(values.length % 2 == 0)
+            return (values[center] + values[center + 1]) / 2.0;
+        else
+            return values[center + 1];
+    }
+
+    public static double mode(double[] values) {
+        if(values.length == 0)
+            return -1.0;
+        HashMap<Double, Integer> map = new HashMap<Double, Integer>();
+        int max = 1;
+        double temp = values[0];
+        for(double value : values) {
+            if(map.get(value) == null) {
+                map.put(value, 1);
+            } else {
+                int cur = map.get(value);
+                map.put(value, ++cur);
+                if(max < cur) {
+                    max = cur;
+                    temp = value;
+                }
+            }
+        }
+        return temp;
+    }
+
+    public static double mmm(double[] values) {
+        return (mean(values) + median(values) + mode(values)) / 3.0;
+    }
+}