feat: [Week 04-5] solve coin-change

Author: Chaedie

coin-change/Chaedie.py

@@ -0,0 +1,28 @@
+"""
+직접 풀지 못해 알고달레 풀이를 참고했습니다. https://www.algodale.com/problems/coin-change/
+
+Solution:
+    1) BFS를 통해 모든 동전을 한번씩 넣어보며 amount와 같아지면 return
+
+(c: coins의 종류 갯수, a: amount)
+Time: O(ca)
+Space: O(a)
+"""
+
+
+class Solution:
+    def coinChange(self, coins: List[int], amount: int) -> int:
+        q = deque([(0, 0)])  # (동전 갯수, 누적 금액)
+        visited = set()
+
+        while q:
+            count, total = q.popleft()
+            if total == amount:
+                return count
+            if total in visited:
+                continue
+            visited.add(total)
+            for coin in coins:
+                if total + coin <= amount:
+                    q.append((count + 1, total + coin))
+        return -1