first commit

Author: kimtth

.gitignore

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+.idea

2-python/ch06/1-1.py

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+class Solution:
+    def isPalindrome(self, s: str) -> bool:
+        strs = []
+        for char in s:
+            if char.isalnum():
+                strs.append(char.lower())
+
+        # 팰린드롬 여부 판별
+        while len(strs) > 1:
+            if strs.pop(0) != strs.pop():
+                return False
+
+        return True

2-python/ch06/1-2.py

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+import collections
+from typing import Deque
+
+
+class Solution:
+    def isPalindrome(self, s: str) -> bool:
+        # 자료형 데크로 선언
+        strs: Deque = collections.deque()
+
+        for char in s:
+            if char.isalnum():
+                strs.append(char.lower())
+
+        while len(strs) > 1:
+            if strs.popleft() != strs.pop():
+                return False
+
+        return True

2-python/ch06/1-3.py

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+import re
+
+
+class Solution:
+    def isPalindrome(self, s: str) -> bool:
+        s = s.lower()
+        # 정규식으로 불필요한 문자 필터링
+        s = re.sub('[^a-z0-9]', '', s)
+
+        return s == s[::-1]  # 슬라이싱

2-python/ch06/1-4.c

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+// C
+bool isPalindrome(char *s) {
+    int bias_left = 0;
+    int bias_right = 1;
+
+    int str_len = strlen(s);
+    for (int i = 0; i < str_len; i++) {
+        // 스킵 포인터 처리
+        while (!isalnum(s[i + bias_left])) {
+            bias_left++;
+            if (i + bias_left == str_len)
+                return true;
+        }
+        while (!isalnum(s[str_len - i - bias_right])) {
+            bias_right++;
+        }
+
+        if (i + bias_left >= str_len - i - bias_right)
+            break;
+        // 팰린드롬 비교
+        if (tolower(s[i + bias_left]) != tolower(s[str_len - i - bias_right]))
+            return false;
+    }
+    return true;
+}

2-python/ch06/2-1.py

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+from typing import List
+
+
+class Solution:
+    def reverseString(self, s: List[str]) -> None:
+        left, right = 0, len(s) - 1
+        while left < right:
+            s[left], s[right] = s[right], s[left]
+            left += 1
+            right -= 1

2-python/ch06/2-2.py

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+from typing import List
+
+
+class Solution:
+    def reverseString(self, s: List[str]) -> None:
+        s.reverse()

2-python/ch06/3-1.py

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+from typing import List
+
+
+class Solution:
+    def reorderLogFiles(self, logs: List[str]) -> List[str]:
+        letters, digits = [], []
+        for log in logs:
+            if log.split()[1].isdigit():
+                digits.append(log)
+            else:
+                letters.append(log)
+
+        # 두 개의 키를 람다 표현식으로 정렬
+        letters.sort(key=lambda x: (x.split()[1:], x.split()[0]))
+        return letters + digits

2-python/ch06/4-1.py

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+import collections
+import re
+from typing import List
+
+
+class Solution:
+    def mostCommonWord(self, paragraph: str, banned: List[str]) -> str:
+        words = [word for word in re.sub(r'[^\w]', ' ', paragraph)
+            .lower().split()
+                 if word not in banned]
+
+        counts = collections.Counter(words)
+        # 가장 흔하게 등장하는 단어의 첫 번째 인덱스 리턴
+        return counts.most_common(1)[0][0]

2-python/ch06/5-1.py

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+import collections
+from typing import List
+
+
+class Solution:
+    def groupAnagrams(self, strs: List[str]) -> List[List[str]]:
+        anagrams = collections.defaultdict(list)
+
+        for word in strs:
+            # 정렬하여 딕셔너리에 추가
+            anagrams[''.join(sorted(word))].append(word)
+        return list(anagrams.values())