Added code for unbounded knapsack in C++ (#1428)

* Added code for unbounded knapsack in C++

* Added unbounded knapsack code

* Moved time complexity below test cases

* Update unbounded_knapsack.cpp

Co-authored-by: Tarun Yadav <[email protected]>

Author: SAY-droid427

Algorithm/DP/readme.md

@@ -46,4 +46,5 @@ be avoided by constructinng a temporary array dp[] and memoizing the computed va
 - Painting Fence Algorithm ----> [Python](/Code/Python/PaintFenceAlgo.py) | [Java](/Code/Java/Paint_fence_algo.java)
 - Shortest Common Supersequence ---->[C++](/Code/C++/print_shortest_supersequence.cpp)
 - Word Wrap Problem ----> [C++](/Code/C++/word_wrap.cpp)
+- Unbounded Knapsack ----> [C++](/Code/C++/unbounded_knapsack.cpp)
 - Painting Fence algorithm ----> [C++](/Code/C++/paint_fence.cpp)

Code/C++/unbounded_knapsack.cpp

@@ -0,0 +1,75 @@
+/* Unbounded Knapsack
+Given:  a knapsack of weight W and n number of items
+Task: find the maximum value of items that can be packed into the knapsack if unlimited number of each item can be included
+*/
+
+#include <bits/stdc++.h>
+using namespace std;
+int Knapsack(int w[], int val[], int n, int W)
+{
+    //Initialization of the array
+    int dp[n + 1][W + 1];
+
+    //Base conditions
+    for (int i = 0; i < n + 1; i++)
+    {
+        for (int j = 0; j < W + 1; j++)
+        {
+            if (i == 0 || j == 0)
+                dp[i][j] = 0;
+        }
+    }
+
+    for (int i = 1; i < n + 1; i++)
+    {
+        for (int j = 1; j < W + 1; j++)
+        {
+            if (w[i - 1] <= j)
+                dp[i][j] = max((val[i - 1] + dp[i][j - w[i - 1]]), dp[i - 1][j]);
+            else
+                dp[i][j] = dp[i - 1][j];
+        }
+    }
+    return dp[n][W];
+}
+int main()
+{
+    int n;
+    cin >> n;
+    int w[n], val[n];
+    for (int i = 0; i < n; i++)
+        cin >> w[i] >> val[i];
+    int W;
+    cin >> W;
+    cout << Knapsack(w, val, n, W);
+}
+
+/*
+TEST CASE 1:
+
+INPUT:
+5
+10 200
+5 60
+3 90
+2 10
+1 6
+20
+
+OUTPUT:
+552
+
+TEST CASE 2:
+
+INPUT:
+2
+10 100
+2 40
+15
+
+OUTPUT:
+280
+
+Time Complexity: O(N*W)
+Space Complexity: O(N*W)
+*/