refactor: removeDuplicates

Author: zohrehKazemianpour

Sprint-1/JavaScript/removeDuplicates/removeDuplicates.mjs

@@ -1,36 +1,30 @@
 /**
  * Remove duplicate values from a sequence, preserving the order of the first occurrence of each value.
  *
- * Time Complexity:
- * Space Complexity:
- * Optimal Time Complexity:
+ * Time Complexity: O(n) - where n is the length of the input sequence, as we need to iterate through it once to create the Set.
+ * Space Complexity: O(n) - in the worst case, if all elements are unique, the Set will contain all elements of the input sequence. so we need memory to store the unique elements.
+ * Optimal Time Complexity: O(n)- using a Set to track seen values allows us to achieve linear time complexity for removing duplicates. 
  *
  * @param {Array} inputSequence - Sequence to remove duplicates from
  * @returns {Array} New sequence with duplicates removed
  */
 export function removeDuplicates(inputSequence) {
+ 
+  return [...new Set(inputSequence)];
+}
+
+
+// approach 2: map and look up object
+/*export function removeDuplicates(inputSequence) {
+  const seen = {};
   const uniqueItems = [];
 
-  for (
-    let currentIndex = 0;
-    currentIndex < inputSequence.length;
-    currentIndex++
-  ) {
-    let isDuplicate = false;
-    for (
-      let compareIndex = 0;
-      compareIndex < uniqueItems.length;
-      compareIndex++
-    ) {
-      if (inputSequence[currentIndex] === uniqueItems[compareIndex]) {
-        isDuplicate = true;
-        break;
-      }
-    }
-    if (!isDuplicate) {
-      uniqueItems.push(inputSequence[currentIndex]);
+  for (const item of inputSequence) {
+    if (!seen[item]) {
+      seen[item] = true;
+      uniqueItems.push(item);
     }
   }
 
   return uniqueItems;
-}
+}*/