From 09b4f02eadfffe2e4b50929271fabb9542c94ed4 Mon Sep 17 00:00:00 2001
From: changhyumm <kch9132@gmail.com>
Date: Thu, 18 Dec 2025 23:33:05 +0900
Subject: [PATCH 1/6] valid parentheses

---
 container-with-most-water/changhyumm.py |  0
 valid-parentheses/changhyumm.py         | 20 ++++++++++++++++++++
 2 files changed, 20 insertions(+)
 create mode 100644 container-with-most-water/changhyumm.py
 create mode 100644 valid-parentheses/changhyumm.py

diff --git a/container-with-most-water/changhyumm.py b/container-with-most-water/changhyumm.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/valid-parentheses/changhyumm.py b/valid-parentheses/changhyumm.py
new file mode 100644
index 0000000000..dff39f8548
--- /dev/null
+++ b/valid-parentheses/changhyumm.py
@@ -0,0 +1,20 @@
+class Solution:
+    def isValid(self, s: str) -> bool:
+        brackets = {"(": ")", "{": "}", "[": "]"}
+        stack = []
+        # 괄호의 특성상 stack 자료구조 활용
+        # 시간 복잡도 O(n)
+        # 공간 복잡도 O(n)
+        for string in s:
+            if string not in brackets:
+                if len(stack) == 0:
+                    return False
+                else:
+                    target = stack.pop()
+                    if string != target:
+                        return False
+            else:
+                stack.append(brackets[string])
+        if stack:
+            return False
+        return True

From e33db1cd7969e809c4af0bf21c712463f4af8796 Mon Sep 17 00:00:00 2001
From: changhyumm <kch9132@gmail.com>
Date: Thu, 18 Dec 2025 23:33:34 +0900
Subject: [PATCH 2/6] container with most water

---
 container-with-most-water/changhyumm.py | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/container-with-most-water/changhyumm.py b/container-with-most-water/changhyumm.py
index e69de29bb2..99629993e2 100644
--- a/container-with-most-water/changhyumm.py
+++ b/container-with-most-water/changhyumm.py
@@ -0,0 +1,23 @@
+class Solution:
+    def maxArea(self, height: List[int]) -> int:
+        # 시간복잡도 O(n2)으로 타임아웃
+        # max_amount = 0
+        # for i in range(len(height) - 1):
+        #     for j in range(i + 1, len(height)):
+        #         amount = (j-i) * min(height[i], height[j])
+        #         max_amount = max(amount, max_amount)
+        # return max_amount
+        
+        # 투포인터 활용
+        # 시간복잡도 O(n)
+        max_amount = 0
+        left = 0
+        right = len(height) - 1
+        while left < right:
+            amount = (right - left) * min(height[left], height[right])
+            max_amount = max(amount, max_amount)
+            if height[left] < height[right]:
+                left += 1
+            else:
+                right -= 1
+        return max_amount

From 7cb90cc20c2d4e149fd8723fd6f0ff6f6c52afe4 Mon Sep 17 00:00:00 2001
From: changhyumm <kch9132@gmail.com>
Date: Thu, 18 Dec 2025 23:49:23 +0900
Subject: [PATCH 3/6] week5 - 1

---
 best-time-to-buy-and-sell-stock/changhyumm.py | 9 +++++++++
 1 file changed, 9 insertions(+)
 create mode 100644 best-time-to-buy-and-sell-stock/changhyumm.py

diff --git a/best-time-to-buy-and-sell-stock/changhyumm.py b/best-time-to-buy-and-sell-stock/changhyumm.py
new file mode 100644
index 0000000000..9a824aea99
--- /dev/null
+++ b/best-time-to-buy-and-sell-stock/changhyumm.py
@@ -0,0 +1,9 @@
+class Solution:
+    def maxProfit(self, prices: List[int]) -> int:
+        min_price = prices[0]
+        max_profit = 0
+        for i in range(0, len(prices) - 1):
+            min_price = min(prices[i], min_price)
+            profit = prices[i+1] - min_price
+            max_profit = max(profit, max_profit)
+        return max_profit
\ No newline at end of file

From cf36d77aeb77ad7a50763fd14735074efa58fd72 Mon Sep 17 00:00:00 2001
From: changhyumm <kch9132@gmail.com>
Date: Thu, 18 Dec 2025 23:51:22 +0900
Subject: [PATCH 4/6] line indent

---
 best-time-to-buy-and-sell-stock/changhyumm.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/best-time-to-buy-and-sell-stock/changhyumm.py b/best-time-to-buy-and-sell-stock/changhyumm.py
index 9a824aea99..ed574fb68e 100644
--- a/best-time-to-buy-and-sell-stock/changhyumm.py
+++ b/best-time-to-buy-and-sell-stock/changhyumm.py
@@ -6,4 +6,4 @@ def maxProfit(self, prices: List[int]) -> int:
             min_price = min(prices[i], min_price)
             profit = prices[i+1] - min_price
             max_profit = max(profit, max_profit)
-        return max_profit
\ No newline at end of file
+        return max_profit

From 6ae8b94c8556aff972ae41d36c75f46a3bbf2485 Mon Sep 17 00:00:00 2001
From: changhyumm <kch9132@gmail.com>
Date: Sat, 20 Dec 2025 02:01:19 +0900
Subject: [PATCH 5/6] design-add-and-search-words-data-structure

---
 .../changhyumm.py                             | 40 +++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 design-add-and-search-words-data-structure/changhyumm.py

diff --git a/design-add-and-search-words-data-structure/changhyumm.py b/design-add-and-search-words-data-structure/changhyumm.py
new file mode 100644
index 0000000000..d7329c240b
--- /dev/null
+++ b/design-add-and-search-words-data-structure/changhyumm.py
@@ -0,0 +1,40 @@
+# prefix 기반으로 탐색할 수 있는 트라이노드 자료구조 활용
+class TrieNode:
+    def __init__(self):
+        self.children = {}
+        self.is_ending = False
+
+class WordDictionary:
+
+    def __init__(self):
+        self.root = TrieNode()
+
+    def addWord(self, word: str) -> None:
+        current_node = self.root
+        for char in word:
+            if char not in current_node.children:
+                current_node.children[char] = TrieNode()
+            current_node = current_node.children[char]
+        current_node.is_ending = True
+
+    def search(self, word):
+        def dfs(node, index):
+            # 단어자리수만큼 왔고, 끝단어인경우 찾기 성공
+            if index == len(word):
+                return node.is_ending
+            # 와일드카드인 경우 자식들 전부 탐색
+            if word[index] == ".":
+                for child in node.children.values():
+                    if dfs(child, index+1):
+                        return True
+            # 일반적인 경우 다음 자식 탐색
+            if word[index] in node.children:
+                return dfs(node.children[word[index]], index+1)
+            return False
+        return dfs(self.root, 0)
+        
+
+# Your WordDictionary object will be instantiated and called as such:
+# obj = WordDictionary()
+# obj.addWord(word)
+# param_2 = obj.search(word)
\ No newline at end of file

From c6f5295861f8dbb7987e13f51eed46208d02b1a0 Mon Sep 17 00:00:00 2001
From: changhyumm <kch9132@gmail.com>
Date: Sat, 20 Dec 2025 02:49:39 +0900
Subject: [PATCH 6/6] longest-increasing-subsequence

---
 longest-increasing-subsequence/changhyumm.py | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100644 longest-increasing-subsequence/changhyumm.py

diff --git a/longest-increasing-subsequence/changhyumm.py b/longest-increasing-subsequence/changhyumm.py
new file mode 100644
index 0000000000..5c5fc00e63
--- /dev/null
+++ b/longest-increasing-subsequence/changhyumm.py
@@ -0,0 +1,14 @@
+class Solution:
+    def lengthOfLIS(self, nums: List[int]) -> int:
+        # dp[i] = nums[0]부터 nums[i]까지의 LIS 길이
+        # 처음은 1
+        n = len(nums)
+        dp = [1] * n
+
+        for i in range(1, n):
+            for j in range(i):
+                if nums[j] < nums[i]:
+                    # nums[i]가 더 큰 경우 길이 + 1
+                    dp[i] = max(dp[i], dp[j] + 1)
+        
+        return max(dp) # 전체 중 최대
\ No newline at end of file