diff --git a/3sum/gcount85.py b/3sum/jamiebase.py
similarity index 100%
rename from 3sum/gcount85.py
rename to 3sum/jamiebase.py
diff --git a/best-time-to-buy-and-sell-stock/gcount85.py b/best-time-to-buy-and-sell-stock/jamiebase.py
similarity index 100%
rename from best-time-to-buy-and-sell-stock/gcount85.py
rename to best-time-to-buy-and-sell-stock/jamiebase.py
diff --git a/climbing-stairs/gcount85.py b/climbing-stairs/jamiebase.py
similarity index 100%
rename from climbing-stairs/gcount85.py
rename to climbing-stairs/jamiebase.py
diff --git a/coin-change/gcount85.py b/coin-change/jamiebase.py
similarity index 100%
rename from coin-change/gcount85.py
rename to coin-change/jamiebase.py
diff --git a/combination-sum/gcount85.py b/combination-sum/jamiebase.py
similarity index 100%
rename from combination-sum/gcount85.py
rename to combination-sum/jamiebase.py
diff --git a/container-with-most-water/gcount85.py b/container-with-most-water/jamiebase.py
similarity index 100%
rename from container-with-most-water/gcount85.py
rename to container-with-most-water/jamiebase.py
diff --git a/contains-duplicate/gcount85.py b/contains-duplicate/jamiebase.py
similarity index 100%
rename from contains-duplicate/gcount85.py
rename to contains-duplicate/jamiebase.py
diff --git a/decode-ways/gcount85.py b/decode-ways/jamiebase.py
similarity index 100%
rename from decode-ways/gcount85.py
rename to decode-ways/jamiebase.py
diff --git a/find-minimum-in-rotated-sorted-array/gcount85.py b/find-minimum-in-rotated-sorted-array/jamiebase.py
similarity index 100%
rename from find-minimum-in-rotated-sorted-array/gcount85.py
rename to find-minimum-in-rotated-sorted-array/jamiebase.py
diff --git a/group-anagrams/gcount85.py b/group-anagrams/jamiebase.py
similarity index 100%
rename from group-anagrams/gcount85.py
rename to group-anagrams/jamiebase.py
diff --git a/house-robber/gcount85.py b/house-robber/jamiebase.py
similarity index 100%
rename from house-robber/gcount85.py
rename to house-robber/jamiebase.py
diff --git a/implement-trie-prefix-tree/gcount85.py b/implement-trie-prefix-tree/jamiebase.py
similarity index 100%
rename from implement-trie-prefix-tree/gcount85.py
rename to implement-trie-prefix-tree/jamiebase.py
diff --git a/longest-consecutive-sequence/gcount85.py b/longest-consecutive-sequence/jamiebase.py
similarity index 100%
rename from longest-consecutive-sequence/gcount85.py
rename to longest-consecutive-sequence/jamiebase.py
diff --git a/longest-increasing-subsequence/gcount85.py b/longest-increasing-subsequence/jamiebase.py
similarity index 100%
rename from longest-increasing-subsequence/gcount85.py
rename to longest-increasing-subsequence/jamiebase.py
diff --git a/longest-substring-without-repeating-characters/jamiebase.py b/longest-substring-without-repeating-characters/jamiebase.py
new file mode 100644
index 0000000000..2701a819d3
--- /dev/null
+++ b/longest-substring-without-repeating-characters/jamiebase.py
@@ -0,0 +1,33 @@
+"""
+# Approach
+슬라이딩 윈도우를 사용한다.
+right 포인터를 하나씩 이동시키면서 문자열을 확장하고,
+이미 등장한 문자를 만나면 해당 문자의 마지막 위치를 기준으로 left 포인터를 이동시켜 중복이 없는 구간을 유지한다.
+각 단계에서 현재 윈도우의 길이를 계산하여 최대값을 갱신한다.
+
+# Complexity
+문자열 길이를 N이라고 할 때, 문자 종류 수를 K라고 할 때
+- Time complexity: O(N)
+- Space complexity: O(K)
+"""
+
+
+class Solution:
+    def lengthOfLongestSubstring(self, s: str) -> int:
+        last_seen = {}  # 문자 -> 마지막으로 등장한 인덱스
+        left = 0  # 현재 윈도우의 시작 위치
+        answer = 0  # 최대 길이 저장
+
+        for right, ch in enumerate(s):
+            # 현재 문자가 이전에 등장했고,
+            # 그 위치가 현재 윈도우 안에 있다면 left 이동
+            if ch in last_seen and last_seen[ch] >= left:
+                left = last_seen[ch] + 1
+
+            # 현재 문자의 마지막 위치 갱신
+            last_seen[ch] = right
+
+            # 현재 윈도우 길이 계산 및 최대값 갱신
+            answer = max(answer, right - left + 1)
+
+        return answer
diff --git a/maximum-depth-of-binary-tree/gcount85.py b/maximum-depth-of-binary-tree/jamiebase.py
similarity index 100%
rename from maximum-depth-of-binary-tree/gcount85.py
rename to maximum-depth-of-binary-tree/jamiebase.py
diff --git a/maximum-subarray/gcount85.py b/maximum-subarray/jamiebase.py
similarity index 100%
rename from maximum-subarray/gcount85.py
rename to maximum-subarray/jamiebase.py
diff --git a/merge-two-sorted-lists/gcount85.py b/merge-two-sorted-lists/jamiebase.py
similarity index 100%
rename from merge-two-sorted-lists/gcount85.py
rename to merge-two-sorted-lists/jamiebase.py
diff --git a/number-of-1-bits/gcount85.py b/number-of-1-bits/jamiebase.py
similarity index 100%
rename from number-of-1-bits/gcount85.py
rename to number-of-1-bits/jamiebase.py
diff --git a/number-of-islands/jamiebase.py b/number-of-islands/jamiebase.py
new file mode 100644
index 0000000000..83a90ca814
--- /dev/null
+++ b/number-of-islands/jamiebase.py
@@ -0,0 +1,45 @@
+"""
+# Approach
+Grid의 원소에 일일이 dfs를 수행하되 값이 "1"(=육지)인 경우만 탐색을 수행합니다.
+이때 방문한 노드는 값을 "-1"로 변경하여 방문 체크합니다.
+
+# Complexity
+Grid의 rows = M, cols = N이라고 할 때,
+- Time complexity: O(M*N)
+- Space complexity: visited set 최대 O(M*N)
+"""
+
+
+class Solution:
+    def numIslands(self, grid: List[List[str]]) -> int:
+        answer = 0
+        direction = [(0, 1), (0, -1), (1, 0), (-1, 0)]
+        row = len(grid)
+        col = len(grid[0])
+
+        def can_go(x, y, row, col):
+            if x < 0 or y < 0 or x >= row or y >= col:
+                return False
+            if grid[x][y] == "0":
+                return False
+            return True
+
+        def dfs(x, y, row, col):
+            for dx, dy in direction:
+                nx, ny = x + dx, y + dy
+                if not can_go(nx, ny, row, col):
+                    continue
+                if grid[nx][ny] == "-1":  # 방문 확인
+                    continue
+                grid[nx][ny] = "-1"  # 방문 처리
+                dfs(nx, ny, row, col)
+
+        for x, row_list in enumerate(grid):
+            for y, value in enumerate(row_list):
+                if value != "1":
+                    continue
+                grid[x][y] = "-1"  # 방문 확인
+                dfs(x, y, row, col)
+                answer += 1
+
+        return answer
diff --git a/product-of-array-except-self/gcount85.py b/product-of-array-except-self/jamiebase.py
similarity index 100%
rename from product-of-array-except-self/gcount85.py
rename to product-of-array-except-self/jamiebase.py
diff --git a/reverse-linked-list/jamiebase.py b/reverse-linked-list/jamiebase.py
new file mode 100644
index 0000000000..4059965740
--- /dev/null
+++ b/reverse-linked-list/jamiebase.py
@@ -0,0 +1,22 @@
+"""
+# Approach
+이전 노드, 현재 노드, 다음 노드를 저장한 뒤, 현재 노드가 이전 노드를 가리키도록 방향을 바꾸고,
+이전 노드와 현재 노드 포인터를 이동시킵니다.
+
+# Complexity
+List의 길이를 N이라고 할 떄
+- Time complexity: O(N)
+- Space complexity: O(1)
+"""
+
+
+class Solution:
+    def reverseList(self, head: Optional[ListNode]) -> Optional[ListNode]:
+        prev = None
+        cur = head
+        while cur:
+            nxt = cur.next  # 1. 다음 노드 저장
+            cur.next = prev  # 2. 방향 뒤집기
+            prev = cur  # 3. prev 이동
+            cur = nxt  # 4. cur 이동
+        return prev
diff --git a/set-matrix-zeroes/jamiebase.py b/set-matrix-zeroes/jamiebase.py
new file mode 100644
index 0000000000..f9f51d4c9d
--- /dev/null
+++ b/set-matrix-zeroes/jamiebase.py
@@ -0,0 +1,34 @@
+"""
+# Approach
+matrix를 순회하며 값이 0인 행과 열의 번호를 기록합니다.
+기록한 것을 토대로 다시 matrix를 순회하며 0으로 채웁니다.
+
+# Complexity
+matrix의 행 크기를 M, 열 크기를 N이라고 할 때
+- Time complexity: O(MN)
+- Space complexity: O(M+N)
+"""
+
+
+class Solution:
+    def setZeroes(self, matrix: list[list[int]]) -> None:
+        """
+        Do not return anything, modify matrix in-place instead.
+        """
+
+        rows, cols = len(matrix), len(matrix[0])
+        zero_rows = set()
+        zero_cols = set()
+        for x, row in enumerate(matrix):
+            for y, value in enumerate(row):
+                if value == 0:
+                    zero_rows.add(x)
+                    zero_cols.add(y)
+
+        for x in zero_rows:
+            for i in range(cols):
+                matrix[x][i] = 0
+
+        for y in zero_cols:
+            for i in range(rows):
+                matrix[i][y] = 0
diff --git a/spiral-matrix/gcount85.py b/spiral-matrix/jamiebase.py
similarity index 100%
rename from spiral-matrix/gcount85.py
rename to spiral-matrix/jamiebase.py
diff --git a/top-k-frequent-elements/gcount85.py b/top-k-frequent-elements/jamiebase.py
similarity index 100%
rename from top-k-frequent-elements/gcount85.py
rename to top-k-frequent-elements/jamiebase.py
diff --git a/two-sum/gcount85.py b/two-sum/jamiebase.py
similarity index 100%
rename from two-sum/gcount85.py
rename to two-sum/jamiebase.py
diff --git a/unique-paths/jamiebase.py b/unique-paths/jamiebase.py
new file mode 100644
index 0000000000..feee38c30e
--- /dev/null
+++ b/unique-paths/jamiebase.py
@@ -0,0 +1,16 @@
+"""
+# Approach
+(0,0) -> (m-1, n-1)로 가기 위해서는 아래로는 m-1회, 우측으로 n-1회 이동해야 합니다.
+도합 m+n-2회 이동해야 합니다. 그 이동 경로 중에서 방향 전환(우측 이동 혹은 아래쪽 이동)을 하는 경우의 수를 계산하여 unique path를 구합니다.
+
+# Complexity
+- Time complexity: math.comb는 거의 상수 시간으로 취급하므로 O(1)
+- Space complexity: O(1)
+"""
+
+import math
+
+
+class Solution:
+    def uniquePaths(self, m: int, n: int) -> int:
+        return math.comb(m + n - 2, m - 1)
diff --git a/valid-anagram/gcount85.py b/valid-anagram/jamiebase.py
similarity index 100%
rename from valid-anagram/gcount85.py
rename to valid-anagram/jamiebase.py
diff --git a/valid-palindrome/gcount85.py b/valid-palindrome/jamiebase.py
similarity index 100%
rename from valid-palindrome/gcount85.py
rename to valid-palindrome/jamiebase.py
diff --git a/valid-parentheses/gcount85.py b/valid-parentheses/jamiebase.py
similarity index 100%
rename from valid-parentheses/gcount85.py
rename to valid-parentheses/jamiebase.py
diff --git a/validate-binary-search-tree/gcount85.py b/validate-binary-search-tree/jamiebase.py
similarity index 100%
rename from validate-binary-search-tree/gcount85.py
rename to validate-binary-search-tree/jamiebase.py
diff --git a/word-break/gcount85.py b/word-break/jamiebase.py
similarity index 100%
rename from word-break/gcount85.py
rename to word-break/jamiebase.py
diff --git a/word-search/gcount85.py b/word-search/jamiebase.py
similarity index 100%
rename from word-search/gcount85.py
rename to word-search/jamiebase.py