updated

Author: bhishma620

src/main/java/com/thealgorithms/dynamicprogramming/Sum_Of_Subset.java

@@ -6,24 +6,36 @@ public static void main(String[] args) {
         int[] arr = {7, 3, 2, 5, 8};
         int Key = 14;
 
-        if (subsetSum(arr, arr.length - 1, Key)) {
+        if (subsetSum(arr, arr.length, Key)) {
             System.out.print("Yes, that sum exists");
         } else {
             System.out.print("Nope, that number does not exist");
         }
     }
 
-    public static boolean subsetSum(int[] arr, int num, int Key) {
-        if (Key == 0) {
-            return true;
-        }
-        if (num < 0 || Key < 0) {
-            return false;
+    static boolean subsetSum(int[] arr, int n, int Key) {
+        boolean[] prev = new boolean[Key + 1];
+
+        prev[0] = true;
+
+        if (arr[0] <= Key) {
+            prev[arr[0]] = true;
         }
 
-        boolean include = subsetSum(arr, num - 1, Key - arr[num]);
-        boolean exclude = subsetSum(arr, num - 1, Key);
+        for (int ind = 1; ind < n; ind++) {
+            boolean[] cur = new boolean[Key + 1];
+            cur[0] = true;
+            for (int target = 1; target <= Key; target++) {
+                boolean notTaken = prev[target];
+                boolean taken = false;
+                if (arr[ind] <= target) {
+                    taken = prev[target - arr[ind]];
+                }
+                cur[target] = notTaken || taken;
+            }
+            prev = cur;
+        }
 
-        return include || exclude;
+        return prev[Key];
     }
 }