diff --git a/combination-sum/iam-edwin.py b/combination-sum/iam-edwin.py
new file mode 100644
index 000000000..6d8ef8b94
--- /dev/null
+++ b/combination-sum/iam-edwin.py
@@ -0,0 +1,20 @@
+from typing import List
+
+
+class Solution:
+    def combinationSum(self, candidates: List[int], target: int) -> List[List[int]]:
+        result = [[[] for _ in range(target + 1)] for _ in range(len(candidates))]
+
+        for index in range(len(candidates)):
+            num = candidates[index]
+            for subTarget in range(1, target + 1):
+                maxUseCount = subTarget // num
+                for useCount in range(0, maxUseCount + 1):
+                    subSubTarget = subTarget - num * useCount
+                    if subSubTarget == 0:
+                        result[index][subTarget].append([num] * useCount)
+                    else:
+                        for item in result[index - 1][subSubTarget]:
+                            result[index][subTarget].append(item + [num] * useCount)
+
+        return result[len(candidates) - 1][target]
diff --git a/number-of-1-bits/iam-edwin.py b/number-of-1-bits/iam-edwin.py
new file mode 100644
index 000000000..78cf09236
--- /dev/null
+++ b/number-of-1-bits/iam-edwin.py
@@ -0,0 +1,4 @@
+class Solution:
+    def hammingWeight(self, n: int) -> int:
+        binaryString = bin(n)[2:]
+        return list(binaryString).count("1")
diff --git a/valid-palindrome/iam-edwin.py b/valid-palindrome/iam-edwin.py
new file mode 100644
index 000000000..62da4414b
--- /dev/null
+++ b/valid-palindrome/iam-edwin.py
@@ -0,0 +1,20 @@
+class Solution:
+    def isPalindrome(self, s: str) -> bool:
+        left = 0
+        right = len(s) - 1
+
+        while left < right:
+            while left < len(s) - 1 and not s[left].isalnum():
+                left += 1
+            while right > 0 and not s[right].isalnum():
+                right -= 1
+
+            if left >= right:
+                return True
+            elif s[left].lower() != s[right].lower():
+                return False
+            else:
+                left += 1
+                right -= 1
+
+        return True