add

Author: kamyu104

C++/shopping-offers.cpp

@@ -0,0 +1,31 @@
+// Time:  O(n * 2^n)
+// Space: O(n)
+
+class Solution {
+public:
+    int shoppingOffers(vector<int>& price, vector<vector<int>>& special, vector<int>& needs) {
+        return shoppingOffersHelper(price, special, needs, 0);
+    }
+
+private:
+    int shoppingOffersHelper(const vector<int>& price, const vector<vector<int>>& special, vector<int>& needs, int i) {
+        if (i == special.size()) {
+            return inner_product(price.begin(), price.end(), needs.begin(), 0);
+        }
+
+        int result = shoppingOffersHelper(price, special, needs, i + 1);
+
+        for (int j = 0; j < special[i].size() - 1; ++j) {
+            needs[j] -= special[i][j];
+        }
+        if (all_of(needs.begin(), needs.end(), [](int i) { return i >= 0; })) {
+            result = min(result, special[i].back() + shoppingOffersHelper(price, special, needs, i));
+        }
+        for (int j = 0; j < special[i].size() - 1; ++j) {
+            needs[j] += special[i][j];
+        }
+
+        return result;
+    }
+};
+