From 72d84c11def25ccf900c14c2e7ee5738f0fc0cd5 Mon Sep 17 00:00:00 2001
From: prenastro <prenastro@gmail.com>
Date: Mon, 6 Jul 2026 03:29:40 -0700
Subject: [PATCH] S30 DP-2 Completed

---
 coinchange2.py | 16 ++++++++++++++++
 painthouse.py  | 22 ++++++++++++++++++++++
 2 files changed, 38 insertions(+)
 create mode 100644 coinchange2.py
 create mode 100644 painthouse.py

diff --git a/coinchange2.py b/coinchange2.py
new file mode 100644
index 00000000..8373b44a
--- /dev/null
+++ b/coinchange2.py
@@ -0,0 +1,16 @@
+class Solution:
+    def change(self, amount: int, coins: List[int]) -> int:
+        m = len(coins)
+        n = amount
+
+        dp = [0] * (n + 1)
+        dp[0] = 1
+
+        for i in range(1, m + 1):
+            for j in range(coins[i - 1], n + 1):
+                dp[j] += dp[j - coins[i - 1]]
+
+        return dp[n]
+
+    # TC - O(m*n)
+    # SC - O(n)
\ No newline at end of file
diff --git a/painthouse.py b/painthouse.py
new file mode 100644
index 00000000..30765d00
--- /dev/null
+++ b/painthouse.py
@@ -0,0 +1,22 @@
+class Solution:
+    def minCost(self, costs):
+        m = len(costs)
+        n = len(costs[0])
+
+        colorR = costs[m-1][0]
+        colorB = costs[m-1][1]
+        colorG = costs[m-1][2]
+
+        for i in range(m-2, -1, -1):
+            tempR = colorR
+            tempB = colorB
+
+            colorR = costs[i][0] + min(colorB, colorG)
+            colorB = costs[i][1] + min(tempR, colorG)
+            colorG = costs[i][2] + min(tempR, tempB)
+
+        return min(colorR, colorB, colorG)
+
+
+    # TC - O(n)
+    # SC - O(1) because 2 pointers approach, if we use DP it will be O(n)
\ No newline at end of file