Ordner angelegt für Algodat - Übung 04 - Testat 01

Suchalgorythmen.java

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+import java.util.Arrays;
+import java.util.Random;
+import java.util.stream.IntStream;
+
+public class Suchalgorythmen {
+    public static void main(String[] args) {
+
+        int[] list1 = IntStream.generate(() -> new Random().nextInt(100)).limit(100).toArray();
+        int[] list2 = Arrays.copyOf(list1, list1.length);
+
+        // aufruf lineare Suche
+        System.out.print("COUNTINGSORT: ");
+        long timeStart = System.nanoTime();
+        COUNTINGSORT(list1);
+        long timeEnd = System.nanoTime();
+        // System.out.println(Arrays.toString(list1));
+        System.out.print(" Verlaufszeit: " + (timeEnd - timeStart) + " Nanosek.");
+        System.out.println("");
+
+        // aufruf binäre Suche
+        System.out.print("RADIXSORT: ");
+        timeStart = System.nanoTime();
+        RADIXSORT(list2, 0, list2.length - 1);
+        timeEnd = System.nanoTime();
+        // System.out.println(Arrays.toString(list2));
+        System.out.print(" Verlaufszeit: " + (timeEnd - timeStart) + " Nanosek.");
+        System.out.println("");
+    }
+
+    public static void COUNTINGSORT(int[] elements) {
+        int maxValue = maxValue(elements);
+        int[] counts = new int[maxValue + 1];
+        // Phase 1: Count
+        for (int element : elements) {
+        counts[element]++;
+        }
+        // Phase 2: Aggregate
+        for (int i = 1; i <= maxValue; i++) {
+        counts[i] += counts[i - 1];
+        }
+        // Phase 3: Write to target array
+        int[] target = new int[elements.length];
+        for (int i = elements.length - 1; i >= 0; i--) {
+        int element = elements[i];
+        target[--counts[element]] = element;
+        }
+        // Copy target back to input array
+        //System.arraycopy(target, 0, elements, 0, elements.length); 
+        System.out.println(Arrays.toString(target));
+    }
+
+    public static int maxValue(int[] chars) {
+        int max = chars[0];
+        for (int ktr = 0; ktr < chars.length; ktr++) {
+            if (chars[ktr] > max) {
+                max = chars[ktr];
+            }
+        }
+        return max;
+    }
+    
+    // vorraussetzung: eingabe Array muss sortiert sein
+    public static void RADIXSORT(int arr[], int low, int high) {
+         
+            // Find the maximum number to
+            // know number of digits
+            int m = maxValue(arr);
+         
+            // Do counting sort for every digit.
+            // Note that instead of passing digit
+            // number, exp is passed. exp is 10^i
+            // where i is current digit number
+            for (int exp = 1; m / exp > 0; exp *= 10)
+                COUNTINGSORT(arr, exp);
+    }
+
+    static void random(int arr[], int low, int high) {
+
+        Random rand = new Random();
+        int pivot = rand.nextInt(high - low) + low;
+
+        int temp1 = arr[pivot];
+        arr[pivot] = arr[high];
+        arr[high] = temp1;
+    }
+}