add coin change solution

Author: i-mprovising

coin-change/i-mprovising.py

@@ -0,0 +1,30 @@
+"""
+Time complexity O(len(coins) * amount)
+Space complexity O(amount)
+
+Dynamic programming
+"""
+
+class Solution:
+    def coinChange(self, coins: List[int], amount: int) -> int:
+        coins = sorted(coins)
+        
+        if amount == 0 :
+            return 0
+
+        dp = [0] + [-1 for _ in range(amount)]
+
+        for i in range(coins[0], amount+1):
+            tmp = []
+            for x in coins:
+                if i - x >= 0:
+                    if dp[i - x] != -1:
+                        tmp.append(dp[i - x] + 1)
+            if len(tmp) == 0:
+                dp[i] = -1
+            else:
+                dp[i] = min(tmp)
+
+        if dp[-1] == 0:
+            return -1
+        return dp[-1]