June 2018 Update

Task/Equilibrium-index/Elena/equilibrium-index.elena

@@ -0,0 +1,66 @@
+import extensions.
+import system'routines.
+import system'collections.
+import extensions'routines.
+
+class EquilibriumEnumerator :: Enumerator
+{
+    int        left.
+    int        right.
+    int        index.
+    enumerator en.
+
+    multi constructor new : object
+        <= new enumerator:object.
+
+    constructor new(Enumerator en)
+    [
+        @en := en.
+
+        $self reset.
+    ]
+
+    constructor new(BaseEnumerable list)
+        <= new(list enumerator).
+
+    bool next
+    [
+        index += 1.
+
+        while(en next)
+        [
+            var element := en get.
+            right -= element.
+            bool found := (left == right).
+            left += element.
+
+            if (found)
+            [
+                ^ true
+            ].
+
+            index += 1.
+        ].
+
+        ^ false
+    ]
+
+    reset
+    [
+        en reset.
+
+        left := 0.
+        right := en summarize.
+        index := -1.
+
+        en reset.
+    ]
+
+    get = index.
+}
+
+program =
+[
+    EquilibriumEnumerator new:(-7, 1, 5, 2, -4, 3, 0);
+        forEach:printingLn.
+].