From 07b0eab7aa8ca1165427e1e5b7058fec7dee63cb Mon Sep 17 00:00:00 2001
From: Johan Sandoval <jojo.han718@gmail.com>
Date: Wed, 22 Jul 2026 12:17:30 -0500
Subject: [PATCH] Finish problem
 0003-longest-substring-without-repeating-characters

---
 .../solution.py                                    | 11 +++++++++++
 .../solution_test.py                               | 14 ++++++++++++++
 2 files changed, 25 insertions(+)
 create mode 100644 problems/0003-longest-substring-without-repeating-characters/solution.py
 create mode 100644 problems/0003-longest-substring-without-repeating-characters/solution_test.py

diff --git a/problems/0003-longest-substring-without-repeating-characters/solution.py b/problems/0003-longest-substring-without-repeating-characters/solution.py
new file mode 100644
index 0000000..907d34e
--- /dev/null
+++ b/problems/0003-longest-substring-without-repeating-characters/solution.py
@@ -0,0 +1,11 @@
+class Solution:
+    def lengthOfLongestSubstring(self, s: str) -> int:
+        hash = {}
+        longest = 0
+        start = 0
+        for idx, char in enumerate(s):
+            if char in hash and hash[char] >= start:
+                start = hash[char] + 1
+            hash[char] = idx
+            longest = max(longest, idx - start + 1)
+        return longest
diff --git a/problems/0003-longest-substring-without-repeating-characters/solution_test.py b/problems/0003-longest-substring-without-repeating-characters/solution_test.py
new file mode 100644
index 0000000..6412db4
--- /dev/null
+++ b/problems/0003-longest-substring-without-repeating-characters/solution_test.py
@@ -0,0 +1,14 @@
+import pytest
+from solution import Solution
+
+
+@pytest.mark.parametrize(
+    "s,expected",
+    [
+        ("abcabcbb", 3),
+        ("bbbbb", 1),
+        ("pwwkew", 3),
+    ],
+)
+def test_longest_substring(s, expected):
+    assert Solution().lengthOfLongestSubstring(s) == expected