Knapsack.java

Java/Knapsack.java

@@ -0,0 +1,40 @@
+import java.util.Arrays;
+
+public class Knapsack {
+    public static void main(String args[]) {
+        int w = 10;
+        int n = 4;
+        int[] val = {10, 40, 30, 50};
+        int[] wt = {5, 4, 6, 3};
+
+        // Populate base cases
+        int[][] mat = new int[n + 1][w + 1];
+        for (int r = 0; r < w + 1; r++) {
+            mat[0][r] = 0;
+        }
+        for (int c = 0; c < n + 1; c++) {
+            mat[c][0] = 0;
+        }
+
+        // Main logic
+        for (int item = 1; item <= n; item++) {
+            for (int capacity = 1; capacity <= w; capacity++) {
+                int maxValWithoutCurr = mat[item - 1][capacity]; // This is guaranteed to exist
+                int maxValWithCurr = 0; // We initialize this value to 0
+
+                int weightOfCurr = wt[item - 1]; // We use item -1 to account for the extra row at the top
+                if (capacity >= weightOfCurr) { // We check if the knapsack can fit the current item
+                    maxValWithCurr = val[item - 1]; // If so, maxValWithCurr is at least the value of the current item
+
+                    int remainingCapacity = capacity - weightOfCurr; // remainingCapacity must be at least 0
+                    maxValWithCurr += mat[item - 1][remainingCapacity]; // Add the maximum value obtainable with the remaining capacity
+                }
+
+                mat[item][capacity] = Math.max(maxValWithoutCurr, maxValWithCurr); // Pick the larger of the two
+            }
+        }
+
+        System.out.println(mat[n][w]); // Final answer
+        System.out.println(Arrays.deepToString(mat)); // Visualization of the table
+    }
+}