Add missing lib placeholder

.tool-versions

@@ -0,0 +1 @@
+scarb 2.6.5

concepts/operator-overload/.meta/config.json

@@ -0,0 +1,7 @@
+{
+    "blurb": "<todo>",
+    "authors": [
+        "misicnenad"
+    ],
+    "contributors": []
+}

concepts/operator-overload/about.md

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+# Operator Overload

concepts/operator-overload/introduction.md

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+# Introduction

concepts/operator-overload/links.json

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+[]

concepts/structs/.meta/config.json

@@ -0,0 +1,7 @@
+{
+    "blurb": "<todo>",
+    "authors": [
+        "misicnenad"
+    ],
+    "contributors": []
+}

concepts/structs/about.md

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+# Structs

concepts/structs/introduction.md

@@ -0,0 +1 @@
+# Introduction

concepts/structs/links.json

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+[]

config.json

@@ -105,8 +105,7 @@
         "uuid": "f3b7ce44-1667-42b4-b792-401d36aee2f1",
         "practices": [
           "tuples",
-          "traits",
-          "control-flow"
+          "traits"
         ],
         "prerequisites": [],
         "difficulty": 2
@@ -118,7 +117,7 @@
         "practices": [
           "structs",
           "traits",
-          "control-flow"
+          "operator-overload"
         ],
         "prerequisites": [],
         "difficulty": 4
@@ -183,6 +182,16 @@
       "uuid": "fe83c9a6-cf50-47b1-9993-21ddd1e895ee",
       "slug": "traits",
       "name": "Traits"
+    },
+    {
+      "uuid": "4e1f6433-3125-4428-837d-47b0c10fddea",
+      "slug": "structs",
+      "name": "Structs"
+    },
+    {
+      "uuid": "0b069f59-f8b4-4979-935a-c3172538f4c9",
+      "slug": "operator-overload",
+      "name": "Operator Overload"
     }
   ],
   "key_features": [

exercises/practice/custom-set/.meta/example.cairo

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+use core::clone::Clone;
+use core::array::ArrayTrait;
+use core::box::BoxTrait;
+
+#[derive(Drop, Debug)]
+pub struct CustomSet<T> {
+    pub collection: Array<T>,
+}
+
+pub impl CustomSetEq<
+    T, +Copy<T>, +Drop<T>, +PartialEq<T>, +core::fmt::Display<T>
+> of PartialEq<CustomSet<T>> {
+    fn eq(lhs: @CustomSet<T>, rhs: @CustomSet<T>) -> bool {
+        if lhs.collection.len() != rhs.collection.len() {
+            return false;
+        }
+        lhs.is_subset(rhs) && rhs.is_subset(lhs)
+    }
+
+    fn ne(lhs: @CustomSet<T>, rhs: @CustomSet<T>) -> bool {
+        !(lhs == rhs)
+    }
+}
+
+#[generate_trait]
+pub impl CustomSetImpl<
+    T, +Copy<T>, +Drop<T>, +core::fmt::Display<T>, +PartialEq<T>
+> of CustomSetTrait<T> {
+    fn new(inputs: @Array<T>) -> CustomSet<T> {
+        let mut set = CustomSet::<T> { collection: array![], };
+        let mut i = 0;
+        while let Option::Some(val) = inputs
+            .get(i) {
+                let unboxed = val.unbox();
+                set.add(unboxed.clone());
+                i += 1;
+            };
+        set
+    }
+
+    fn add(ref self: CustomSet<T>, element: T) {
+        if !self.contains(@element) {
+            self.collection.append(element)
+        }
+    }
+
+    fn contains(self: @CustomSet<T>, other: @T) -> bool {
+        let mut is_contained = false;
+        let mut i = 0;
+        while let Option::Some(boxed) = self
+            .collection
+            .get(i) {
+                let val = boxed.unbox();
+                if val == other {
+                    is_contained = true;
+                    break;
+                }
+                i += 1;
+            };
+        is_contained
+    }
+
+    fn is_empty(self: @CustomSet<T>) -> bool {
+        self.collection.is_empty()
+    }
+
+    fn is_subset(self: @CustomSet<T>, other: @CustomSet<T>) -> bool {
+        if self.collection.len() > other.collection.len() {
+            return false;
+        }
+        let mut result = true;
+        let mut i = 0;
+        while let Option::Some(val) = self
+            .collection
+            .get(i) {
+                if !other.contains(val.unbox()) {
+                    result = false;
+                    break;
+                }
+                i += 1;
+            };
+        result
+    }
+
+    fn is_disjoint(self: @CustomSet<T>, other: @CustomSet<T>) -> bool {
+        let mut are_disjoint = true;
+
+        // a more efficient way is to iterate the smaller set
+        let mut to_iterate = self;
+        let mut to_compare = other;
+        if to_iterate.collection.len() > to_compare.collection.len() {
+            to_iterate = other;
+            to_compare = self;
+        };
+
+        let mut i = 0;
+        while let Option::Some(val) = to_iterate
+            .collection
+            .get(i) {
+                if to_compare.contains(val.unbox()) {
+                    are_disjoint = false;
+                    break;
+                }
+                i += 1;
+            };
+
+        are_disjoint
+    }
+
+    #[must_use]
+    fn intersection(self: @CustomSet<T>, other: @CustomSet<T>) -> CustomSet<T> {
+        let mut collection: Array<T> = array![];
+
+        // a more efficient way is to iterate the smaller set
+        let mut to_iterate = self;
+        let mut to_compare = other;
+        if to_iterate.collection.len() > to_compare.collection.len() {
+            to_iterate = other;
+            to_compare = self;
+        };
+
+        let mut i = 0;
+        while let Option::Some(val) = to_iterate
+            .collection
+            .get(i) {
+                let unboxed = val.unbox();
+                if to_compare.contains(unboxed) {
+                    collection.append(*unboxed);
+                }
+                i += 1;
+            };
+
+        CustomSetImpl::<T>::new(@collection)
+    }
+
+    #[must_use]
+    fn union(self: @CustomSet<T>, other: @CustomSet<T>) -> CustomSet<T> {
+        let mut collection: Array<T> = array![];
+        let mut i = 0;
+        while let Option::Some(val) = self
+            .collection
+            .get(i) {
+                collection.append(*val.unbox());
+                i += 1;
+            };
+        i = 0;
+        while let Option::Some(val) = other
+            .collection
+            .get(i) {
+                collection.append(*val.unbox());
+                i += 1;
+            };
+        CustomSetImpl::<T>::new(@collection)
+    }
+
+    #[must_use]
+    fn difference(self: @CustomSet<T>, other: @CustomSet<T>) -> CustomSet<T> {
+        let mut collection: Array<T> = array![];
+        let mut i = 0;
+        while let Option::Some(val) = self
+            .collection
+            .get(i) {
+                let unboxed = val.unbox();
+                if !other.contains(unboxed) {
+                    collection.append(unboxed.clone());
+                }
+                i += 1;
+            };
+        CustomSetImpl::<T>::new(@collection)
+    }
+}
+
+
+#[cfg(test)]
+mod tests;