From 6e5f8f2e787e1eb45b6cfd747398f40a83061127 Mon Sep 17 00:00:00 2001
From: Adrito-M <98008131+Adrito-M@users.noreply.github.com>
Date: Mon, 30 May 2022 23:00:15 +0530
Subject: [PATCH 1/2] Create 0-1 knapsack.cpp

---
 c++/0-1 knapsack.cpp | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 c++/0-1 knapsack.cpp

diff --git a/c++/0-1 knapsack.cpp b/c++/0-1 knapsack.cpp
new file mode 100644
index 0000000..6321f10
--- /dev/null
+++ b/c++/0-1 knapsack.cpp	
@@ -0,0 +1,22 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+
+int weight[] = {10, 20, 30};
+int value[] = {60, 100, 120};
+
+int knapsack(int weight_left, int index) {
+    if (index == -1 or weight_left < weight[index]) return 0;
+    int a = knapsack(weight_left, index-1);
+    int b = knapsack(weight_left - weight[index], index-1) + value[index];
+    return max(a, b);
+}
+
+int main()
+{
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    int bag_weight = 50;
+    int items = 3;
+    cout << knapsack(bag_weight, items);
+}

From 1f7972ab0ffa2693d04646f7241be6a1c07600f7 Mon Sep 17 00:00:00 2001
From: Adrito-M <98008131+Adrito-M@users.noreply.github.com>
Date: Mon, 30 May 2022 23:04:25 +0530
Subject: [PATCH 2/2] Update 0-1 knapsack.cpp

---
 c++/0-1 knapsack.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/c++/0-1 knapsack.cpp b/c++/0-1 knapsack.cpp
index 6321f10..b18583b 100644
--- a/c++/0-1 knapsack.cpp	
+++ b/c++/0-1 knapsack.cpp	
@@ -4,18 +4,21 @@ using namespace std;
 
 int weight[] = {10, 20, 30};
 int value[] = {60, 100, 120};
+int dp[1000][1000];
 
 int knapsack(int weight_left, int index) {
     if (index == -1 or weight_left < weight[index]) return 0;
+    if (~dp[weight_left][index]) return dp[weight_left][index];
     int a = knapsack(weight_left, index-1);
     int b = knapsack(weight_left - weight[index], index-1) + value[index];
-    return max(a, b);
+    return dp[weight_left][index] = max(a, b);
 }
 
 int main()
 {
     ios_base::sync_with_stdio(false);
     cin.tie(NULL);
+    memset(dp, -1, sizeof dp);
     int bag_weight = 50;
     int items = 3;
     cout << knapsack(bag_weight, items);