completed removeDuplicates

Author: TzeMingHo

Sprint-1/JavaScript/removeDuplicates/removeDuplicates.mjs

@@ -1,36 +1,40 @@
 /**
  * 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^2). It takes a loop inside a loop to compare duplicates.
+ * Space Complexity: O(N). The uniqueItems array would grow to N in the worst case.
+ * Optimal Time Complexity: O(N). It only loops once after optimization. 
  *
  * @param {Array} inputSequence - Sequence to remove duplicates from
  * @returns {Array} New sequence with duplicates removed
  */
-export function removeDuplicates(inputSequence) {
-  const uniqueItems = [];
+// export function removeDuplicates(inputSequence) {
+//   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 (
-    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]);
-    }
-  }
+//   return uniqueItems;
+// }
 
-  return uniqueItems;
-}
+export function removeDuplicates(inputSequence) {
+  return [...new Set(inputSequence)];
+}

Sprint-1/Python/remove_duplicates/remove_duplicates.py

@@ -7,19 +7,28 @@ def remove_duplicates(values: Sequence[ItemType]) -> List[ItemType]:
     """
     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^2). It takes a loop inside a loop
+    Space complexity: O(N). The space of unique_items would grow to N in the worst case.
+    Optimal time complexity: O(N). It only loops once after optimization, but the space becomes O(N + N)
     """
-    unique_items = []
+    # unique_items = []
+
+    # for value in values:
+    #     is_duplicate = False
+    #     for existing in unique_items:
+    #         if value == existing:
+    #             is_duplicate = True
+    #             break
+    #     if not is_duplicate:
+    #         unique_items.append(value)
+
+    # return unique_items
 
+    seen = set()
+    unique_items = []
     for value in values:
-        is_duplicate = False
-        for existing in unique_items:
-            if value == existing:
-                is_duplicate = True
-                break
-        if not is_duplicate:
+        if value not in seen:
+            seen.add(value)
             unique_items.append(value)
-
+    
     return unique_items