diff --git a/02_activities/assignments/assignment_1.ipynb b/02_activities/assignments/assignment_1.ipynb
index f02523c4..29122fe3 100644
--- a/02_activities/assignments/assignment_1.ipynb
+++ b/02_activities/assignments/assignment_1.ipynb
@@ -25,9 +25,17 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 1,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "1\n"
+     ]
+    }
+   ],
    "source": [
     "import hashlib\n",
     "\n",
@@ -35,7 +43,7 @@
     "     hash_object = hashlib.sha256(input_string.encode())\n",
     "     hash_int = int(hash_object.hexdigest(), 16)\n",
     "     return (hash_int % 3) + 1\n",
-    "input_string = \"your_first_name_here\"\n",
+    "input_string = \"Isra\"\n",
     "result = hash_to_range(input_string)\n",
     "print(result)\n"
    ]
@@ -165,11 +173,12 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 34,
    "metadata": {},
    "outputs": [],
    "source": [
-    "# Your answer here"
+    "# The problem is to find the first number that is repeated when iterating through the list and return that number, \n",
+    "# if there was no duplicate, return -1"
    ]
   },
   {
@@ -181,11 +190,13 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 15,
    "metadata": {},
    "outputs": [],
    "source": [
-    "# Your answer here"
+    "# nums = [2,1,3,5,3,2], this should return 3\n",
+    "# nums = [5,6,7,8], this should return -1\n",
+    "# nums = [1,2,3,4,4,5,5,6,6,7], this should return 4"
    ]
   },
   {
@@ -198,11 +209,92 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 26,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "3"
+      ]
+     },
+     "execution_count": 26,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "from typing import List\n",
+    "\n",
+    "def first_duplicate(nums: List[int]) -> int:\n",
+    "    found = set()\n",
+    "    for num in nums: \n",
+    "        if num in found:\n",
+    "            return num\n",
+    "        found.add(num)\n",
+    "    return -1\n",
+    "\n",
+    "first_duplicate([2, 1, 3, 5, 3, 2])  "
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 27,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "1"
+      ]
+     },
+     "execution_count": 27,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "first_duplicate([3, 1, 4, 2, 5, 1, 6])"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 28,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "-1"
+      ]
+     },
+     "execution_count": 28,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "first_duplicate([7, 8, 9, 10])"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 29,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "4"
+      ]
+     },
+     "execution_count": 29,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
-    "# Your answer here"
+    "first_duplicate([1,2,3,4,4,5,5,6,6,7])"
    ]
   },
   {
@@ -215,11 +307,15 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 30,
    "metadata": {},
    "outputs": [],
    "source": [
-    "# Your answer here"
+    "# In my code, I used a set to keep track of the the numbers that have already been found. \n",
+    "# As I iterate through the list, I check if the number was already in the set. \n",
+    "# If it was, I will return that number as it is the first duplicate. \n",
+    "# If it wasn't found, I will add it to the set and continue until the end of the list.\n",
+    "# If no duplicates were found, I return -1."
    ]
   },
   {
@@ -232,11 +328,14 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 31,
    "metadata": {},
    "outputs": [],
    "source": [
-    "# Your answer here"
+    "# In terms of time complexity, this solution is O(n) because we only iterate through it once. \n",
+    "# In terms of space complexity, this solution is O(n) in the worst case scenario, if there are no duplicates.\n",
+    "# In the best scenario, if the first two numbers are the same, the space complexity is O(1).\n",
+    "# This solution is effiencet in time complexity but not in space complexity. "
    ]
   },
   {
@@ -249,11 +348,13 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 33,
    "metadata": {},
    "outputs": [],
    "source": [
-    "# Your answer here"
+    "# An alterative solution would be to sort the list and then look for duplicates. \n",
+    "# This would add a time complexity because of the sorting step.\n",
+    "# making the time complexity O(n Log n) but we would need to store anything so the space complexity would be O(1)"
    ]
   },
   {
@@ -301,7 +402,7 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 3 (ipykernel)",
+   "display_name": "dsi_participant",
    "language": "python",
    "name": "python3"
   },
@@ -315,7 +416,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.11.5"
+   "version": "3.9.23"
   }
  },
  "nbformat": 4,