[JiHyeonSu] WEEK 2 solutions

climbing-stairs/JiHyeonSu.py

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+# 피보나치 수열
+# DP Bottom-up
+# 시간복잡도 및 공간복잡도 O(n)
+
+class Solution:
+    def climbStairs(self, n: int) -> int:
+        if (n < 2):
+            return n
+
+        dp = [0] * (n + 1)
+
+        dp[1] = 1
+        dp[2] = 2
+
+        first, second = 1, 2
+
+        for i in range(3, n + 1):
+            dp[i] = dp[i - 1] + dp[i - 2]
+
+        return dp[n]
+

product-of-array-except-self/JiHyeonSu.py

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+class Solution:
+    def productExceptSelf(self, nums: List[int]) -> List[int]:
+        n = len(nums)
+        answer = [1] * n
+
+        left = 1
+        for i in range(n):
+            answer[i] = left
+            left *= nums[i]
+
+        right = 1
+        for i in reversed(range(n)):
+            answer[i] *= right
+            right *= nums[i]
+
+        return answer
+

valid-anagram/JiHyeonSu.py

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+# 재배치하여 다른 문자를 만들 수 있는지 여부
+# 시간복잡도 / 공간복잡도 O(n)
+
+class Solution:
+    def isAnagram(self, s: str, t: str) -> bool:
+        return Counter(s) == Counter(t)
+