diff --git a/src/index.js b/src/index.js
index 253a199..2ae936a 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,31 +1,62 @@
 class Sorter {
-  constructor() {
-    // your implementation
-  }
+    constructor() {
+        this.arr = [];
+        this.compareFunction = (a, b) => a - b;
+    }
 
-  add(element) {
-    // your implementation
-  }
+    get length() {
+        return this.arr.length;
+    }
 
-  at(index) {
-    // your implementation
-  }
+    add(element) {
+        this.arr.push(element);
+    }
 
-  get length() {
-    // your implementation
-  }
+    at(index) {
+        return this.arr[index];
+    }
 
-  toArray() {
-    // your implementation
-  }
+    toArray() {
+        return this.arr;
+    }
 
-  sort(indices) {
-    // your implementation
-  }
+    sort(indices) {
+        let sortedPart = [];
+        indices.sort((a, b) => a - b);
 
-  setComparator(compareFunction) {
-    // your implementation
-  }
+        for (let i in indices) {
+            sortedPart.push(this.arr[indices[i]]);
+        }
+
+        sortedPart.sort(this.compareFunction);
+
+        for (let i = 0; i < indices.length; i++) {
+            this.arr[indices[i]] = sortedPart[i];
+        }
+        return this.arr;
+    }
+
+    setComparator(compareFunction) {
+        compareFunction == undefined ? null : this.compareFunction = compareFunction;
+    }
 }
 
+
+/*let sorter = new Sorter();
+sorter.add(5);
+sorter.add(4);
+sorter.add(3);
+console.log(sorter.toArray());
+sorter.sort([0, 1, 2]);
+console.log(sorter.toArray());
+console.log(sorter.length);
+console.log(typeof sorter);
+sorter.add(1);
+sorter.add(2);
+sorter.add(3);
+sorter.sort[0, 1, 2];
+sorter.sort([0]);
+console.log(sorter.toArray());
+console.log(sorter.toArray() == [1])*/
+
 module.exports = Sorter;
\ No newline at end of file