diff --git a/problem_003/solution.py b/problem_003/solution.py
new file mode 100644
index 0000000..f9a4aa0
--- /dev/null
+++ b/problem_003/solution.py
@@ -0,0 +1,73 @@
+# Extra header to ensure that tests can run individually and as a suite
+#  -------------------------------------------------------------------
+import sys
+from pathlib import Path
+# Add the project root folder to the Python path
+sys.path.append(str(Path(__file__).resolve().parents[1]))
+#  -------------------------------------------------------------------
+
+# Now you can import your wrapper
+from test_runner.wrapper import run_tests
+
+class Solution:
+    def lengthOfLongestSubstring(self, s: str) -> int:
+        # str_start -> str
+        hashMap = {}
+        measuredLengths = {}
+        longest_string = 0
+        current_string = ""
+
+        # Cover edge case where the string has no repeats
+        if len(s) == len(set(s)):
+            return len(s)
+        else:
+            # Iterate over whole string, one character at a time
+            for str in s:
+                # Initial condition, current_string is empty so put the string into it.
+                if not current_string:
+                    current_string = str
+                else:
+                    #TODO: I feel like I can do a much better job than this one... it's messy and slow even if it works.
+                    if str in current_string:
+                        repeat_index = current_string.index(str) + 1
+                        # TODO: I am pretty sure this problem is -- RIGHT HERE -- so I should work on this part harder. If I remove it I miss cases in old tests, but I am assuming this part is the case where I am seeing failures.
+                        # We are finding a new character string, so we should store the old character string length off somewhere.
+                        current_string = current_string[repeat_index:] + str
+                        measuredLengths[str] = len(hashMap[str])
+                    else:
+                        current_string = current_string + str
+
+                count = 0
+                # This is really bad, I know. Fix it.
+                for str2 in current_string:
+                    hashMap[str2] = current_string[count:]
+                    count += 1
+                    
+                    # See if the current value is greater than the last string value found with this length. If so, update the entry.
+
+                    # Attempts to look up the value, and if it isn't found just return 0
+                    lastMeasuredLength = measuredLengths.get(str2, 0)
+
+                    newMeasuredLength = len(hashMap[str2])
+                    if(newMeasuredLength > lastMeasuredLength):
+                        measuredLengths[str2] = len(hashMap[str2])
+
+            # Soo.... now I should be able to iterate through meaturedLengths see the lengths of each string based on it's index. Then I just need to find the max?
+            for character in measuredLengths:
+                length = measuredLengths[character]
+                # print(f"character: {character}, length: {length} ")
+                if length > longest_string:
+                    longest_string = length
+
+            return longest_string
+
+
+if __name__ == "__main__":
+    # Get the directory where this solution.py script lives
+    script_dir = Path(__file__).parent
+    
+    # Join the script's directory with the JSON filename to create a full path
+    # Make sure your file is actually named "test_inputs.json"!
+    test_file_path = script_dir / "test_inputs.json"
+    
+    run_tests(Solution, test_file_path)
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diff --git a/problem_003/test_inputs.json b/problem_003/test_inputs.json
new file mode 100644
index 0000000..0f05783
--- /dev/null
+++ b/problem_003/test_inputs.json
@@ -0,0 +1,37 @@
+{
+    "method": "lengthOfLongestSubstring",
+    "tests": [
+        {
+            "Input": "abcabcbb",
+            "Output": "3"
+        },
+        {
+            "Input": "bbbbb",
+            "Output": "1"
+        },
+        {
+            "Input": "pwwkew",
+            "Output": "3"
+        },
+        {
+            "Input": "a",
+            "Output": "1"
+        },
+        {
+            "Input": " ",
+            "Output": "1"
+        },
+        {
+            "Input": "au",
+            "Output": "2"
+        },
+        {
+            "Input": "aab",
+            "Output": "2"
+        },
+        {
+            "Input": "odgqjxwoupzjiudpadcrozuujz",
+            "Output": "10"
+        }  
+    ]
+}
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