From c41d10abeb4906b2fe4d03dffd926d1413b91cd0 Mon Sep 17 00:00:00 2001
From: Jesse Adams <jda170001@utdallas.edu>
Date: Sun, 20 Sep 2020 16:23:40 -0500
Subject: [PATCH 1/2] Created SubsetSum.java

---
 DynamicProgramming/SubsetSum.java | 57 +++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 DynamicProgramming/SubsetSum.java

diff --git a/DynamicProgramming/SubsetSum.java b/DynamicProgramming/SubsetSum.java
new file mode 100644
index 00000000..80596346
--- /dev/null
+++ b/DynamicProgramming/SubsetSum.java
@@ -0,0 +1,57 @@
+package DynamicProgramming;
+
+public class SubsetSum {
+
+    /*
+    This algorithm will determine if a set of integers contains
+    a subset that sum to a given integer. The algorithm will
+    return true if such a subset exists and false otherwise.
+    This is a dynamic programming implementation.
+     */
+
+    private static boolean subsetSum(int arr[], int n, int sum){
+        boolean isSum[][] = new boolean[n + 2][sum + 1];
+
+        isSum[n + 1][0] = true;
+        for (int i = 1; i <= sum; i++) {
+            isSum[n + 1][i] = false;
+        }
+
+        for (int i = n; i > 0; i--) {
+            isSum[i][0] = true;
+            for (int j = 1; j <= arr[i - 1] - 1; j++) {
+                if (j <= sum) {
+                    isSum[i][j] = isSum[i + 1][j];
+                }
+            }
+            for (int j = arr[i - 1]; j <= sum; j++) {
+                isSum[i][j] = (isSum[i + 1][j] || isSum[i + 1][j - arr[i - 1]]);
+            }
+        }
+
+        return isSum[1][sum];
+    }
+
+    /*
+    This is a driver method to run the algorithm with four
+    test values: the first two should evaluate true, and the
+    last two should evaluate false.
+     */
+    public static void main(String args[]) {
+        int arr[] = new int[]{50, 4, 10, 15, 34};
+        int n = arr.length;
+        // 4 + 10 + 15 + 34 = 64
+        int sum1 = 64;
+        // 50 + 15 + 34 = 99
+        int sum2 = 99;
+        // No subset of the given array will give a sum
+        //  of 5 or 66
+        int sum3 = 5;
+        int sum4 = 66;
+
+        System.out.println(subsetSum(arr, n, sum1));
+        System.out.println(subsetSum(arr, n, sum2));
+        System.out.println(subsetSum(arr, n, sum3));
+        System.out.println(subsetSum(arr, n, sum4));
+    }
+}
\ No newline at end of file

From e5a3e4b479134d9e33ec3a3cdcee9d0def7e8ada Mon Sep 17 00:00:00 2001
From: shellhub <shellhub.me@gmail.com>
Date: Tue, 22 Sep 2020 10:09:04 +0800
Subject: [PATCH 2/2] reformat code

---
 DynamicProgramming/SubsetSum.java | 49 ++++++++++++-------------------
 1 file changed, 19 insertions(+), 30 deletions(-)

diff --git a/DynamicProgramming/SubsetSum.java b/DynamicProgramming/SubsetSum.java
index 80596346..18a35724 100644
--- a/DynamicProgramming/SubsetSum.java
+++ b/DynamicProgramming/SubsetSum.java
@@ -2,15 +2,27 @@ package DynamicProgramming;
 
 public class SubsetSum {
 
-    /*
-    This algorithm will determine if a set of integers contains
-    a subset that sum to a given integer. The algorithm will
-    return true if such a subset exists and false otherwise.
-    This is a dynamic programming implementation.
+    /**
+     * Driver Code
      */
+    public static void main(String[] args) {
+        int[] arr = new int[]{50, 4, 10, 15, 34};
+        assert subsetSum(arr, 64); /* 4 + 10 + 15 + 34 = 64 */
+        assert subsetSum(arr, 99); /* 50 + 15 + 34 = 99 */
+        assert !subsetSum(arr, 5);
+        assert !subsetSum(arr, 66);
+    }
 
-    private static boolean subsetSum(int arr[], int n, int sum){
-        boolean isSum[][] = new boolean[n + 2][sum + 1];
+    /**
+     * Test if a set of integers contains a subset that sum to a given integer.
+     *
+     * @param arr the array contains integers.
+     * @param sum target sum of subset.
+     * @return {@code true} if subset exists, otherwise {@code false}.
+     */
+    private static boolean subsetSum(int[] arr, int sum) {
+        int n = arr.length;
+        boolean[][] isSum = new boolean[n + 2][sum + 1];
 
         isSum[n + 1][0] = true;
         for (int i = 1; i <= sum; i++) {
@@ -31,27 +43,4 @@ public class SubsetSum {
 
         return isSum[1][sum];
     }
-
-    /*
-    This is a driver method to run the algorithm with four
-    test values: the first two should evaluate true, and the
-    last two should evaluate false.
-     */
-    public static void main(String args[]) {
-        int arr[] = new int[]{50, 4, 10, 15, 34};
-        int n = arr.length;
-        // 4 + 10 + 15 + 34 = 64
-        int sum1 = 64;
-        // 50 + 15 + 34 = 99
-        int sum2 = 99;
-        // No subset of the given array will give a sum
-        //  of 5 or 66
-        int sum3 = 5;
-        int sum4 = 66;
-
-        System.out.println(subsetSum(arr, n, sum1));
-        System.out.println(subsetSum(arr, n, sum2));
-        System.out.println(subsetSum(arr, n, sum3));
-        System.out.println(subsetSum(arr, n, sum4));
-    }
 }
\ No newline at end of file