Added groupSum5.java

Author: Alfredo Miranda

java/recursion-2/groupSum5.java

@@ -0,0 +1,25 @@
+/* Given an array of ints, is it possible to choose a group of some of the 
+ * ints, such that the group sums to the given target with these additional 
+ * constraints: all multiples of 5 in the array must be included in the group. 
+ * If the value immediately following a multiple of 5 is 1, it must not be 
+ * chosen. (No loops needed.)
+ */
+public boolean groupSum5(int start, int[] nums, int target) {
+    if(start >= nums.length)
+        return target == 0;
+          
+    if(nums[start] % 5 == 0) {
+        if(start <= nums.length - 2 && nums[start+1] == 1)
+            return groupSum5(start+2, nums, target - nums[start]);
+                            
+        return groupSum5(start+1, nums, target - nums[start]);
+    }
+                                    
+    if(groupSum5(start+1, nums, target - nums[start]))
+        return true;
+                                              
+    if(groupSum5(start+1, nums, target))
+        return true;
+                                                        
+    return false;
+}