diff --git a/Challenge-1/README.md b/Challenge-1/README.md
new file mode 100644
index 0000000..f7c9fcc
--- /dev/null
+++ b/Challenge-1/README.md
@@ -0,0 +1 @@
+saheed muhammed
diff --git a/Challenge-2/solution.py b/Challenge-2/solution.py
new file mode 100644
index 0000000..2f72754
--- /dev/null
+++ b/Challenge-2/solution.py
@@ -0,0 +1,9 @@
+class Solution:
+    def twoSum(self, nums: List[int], target: int) -> List[int]:
+        prev_map=dict()
+        for i, num in enumerate(nums):
+            if target - num in prev_map:
+               return[i, prev_map[target-num]]
+            prev_map[num]=i
+       
+        return -1     
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diff --git a/Challenge-4/Duplicate.py b/Challenge-4/Duplicate.py
new file mode 100644
index 0000000..c99aed3
--- /dev/null
+++ b/Challenge-4/Duplicate.py
@@ -0,0 +1,9 @@
+class Solution:
+    def containsDuplicate(self, nums: List[int]) -> bool:
+        hash_set=set()
+
+        for num in nums:
+            if num in hash_set:
+                return True
+            hash_set.add(num)
+        return False
diff --git a/Challenge-5/solution.js b/Challenge-5/solution.js
new file mode 100644
index 0000000..b1f843f
--- /dev/null
+++ b/Challenge-5/solution.js
@@ -0,0 +1,16 @@
+/**
+ * @param {number} a
+ * @param {number} b
+ * @return {number}
+ */
+var getSum = function(a, b) {
+   
+    while(b){
+      let temp=a
+      a=temp^b
+      b=(temp&b)<<1 
+    }
+    return a
+ 
+    
+};
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diff --git a/Challenge_3/solution.py b/Challenge_3/solution.py
new file mode 100644
index 0000000..da69616
--- /dev/null
+++ b/Challenge_3/solution.py
@@ -0,0 +1,16 @@
+class Solution:
+    def maxProfit(self, prices: List[int]) -> int:
+        # tow pointer
+        left, right = 0, 1
+        profit = 0
+
+        while right < len(prices):
+        # Check if profitable
+            if prices[right] > prices[left]:
+                profit = max(profit, prices[right] - prices[left])
+            else:
+                left = right  # Update left pointer to the current right 
+
+            right += 1  # Move the right pointer forward
+
+        return profit
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