segregate even and odd nos : done

Author: Ram swaroop

src/me/ramswaroop/arrays/SegregateEvenAndOddNos.java

@@ -0,0 +1,50 @@
+package me.ramswaroop.arrays;
+
+import java.util.Arrays;
+
+/**
+ * Created by IntelliJ IDEA.
+ *
+ * @author: ramswaroop
+ * @date: 7/31/15
+ * @time: 5:13 PM
+ */
+public class SegregateEvenAndOddNos {
+
+    /**
+     * Segregate even and odd numbers by traversing the
+     * array {@param a} only once.
+     * <p/>
+     * This is similar to {@link me.ramswaroop.arrays.Segregate0sAnd1s}.
+     *
+     * @param a
+     */
+    public static void segregateEvenAndOddNos(int[] a) {
+        for (int i = 0, j = a.length - 1; i < j; ) {
+            if (a[i] % 2 != 0 && a[j] % 2 == 0) {
+                // swap
+                a[i] = a[i] + a[j];
+                a[j] = a[i] - a[j];
+                a[i] = a[i] - a[j];
+                i++;
+                j--;
+            } else if (a[i] % 2 == 0 && a[j] % 2 == 0) {
+                i++;
+            } else if (a[i] % 2 != 0 && a[j] % 2 != 0) {
+                j--;
+            } else {
+                i++;
+                j--;
+            }
+        }
+    }
+
+    public static void main(String a[]) {
+        int[] ar = new int[]{12, 34, 45, 9, 8, 90, 3};
+        segregateEvenAndOddNos(ar);
+        System.out.println(Arrays.toString(ar));
+        int[] ar1 = new int[]{34, 1, 45, 9, 8, 67, 3, 56, 78, 79, 101, 100};
+        segregateEvenAndOddNos(ar1);
+        System.out.println(Arrays.toString(ar1));
+    }
+}