return sum to K

Author: anmolpant

Data Structures in Java/Level 1/Lecture 4 - Recursion 2/Assignments/Recursion2_ReturnSubsetsSumToK.java

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+
+public class Recursion2_ReturnSubsetsSumToK {
+    private static int[][] subsetsSumK (int input[], int k, int start, int end){
+        
+        if (start > end){
+            if (k==0){
+                int[][] output = new int[1][0];
+                return output;
+            }
+            else{
+                int[][] output = new int[0][0];
+                return output;
+            }
+        }
+        
+        int[][] smallAns1 = subsetsSumK(input, k-input[start], start + 1, end);
+        int[][] smallAns2 = subsetsSumK(input, k, start+1, end);
+        
+        //initialize rows
+        int[][] ans = new int[smallAns1.length + smallAns2.length][];
+        //loop over smallAns1 rows
+        for(int i = 0; i<smallAns1.length;i++){
+            //add columns len + 1
+            ans[i] = new int[smallAns1[i].length + 1];
+            //add first element
+            ans[i][0] = input[start];
+            //add remaining elements
+            for(int j = 0; j<smallAns1[i].length; j++){
+                ans[i][j+1] = smallAns1[i][j];
+            }
+        }
+        
+        //copy smallAns2 k elements
+        
+        //loop over smallAns2 elements
+        for(int i = 0; i<smallAns2.length; i++){
+            //add columns after smallAns1 ki length
+            ans[i + smallAns1.length] = new int[smallAns2[i].length];
+            for(int j = 0; j<smallAns2[i].length; j++){
+                ans[i + smallAns1.length][j] = smallAns2[i][j];
+            }
+        }
+        
+        return ans;
+    }
+
+	// Return a 2D array that contains all the subsets which sum to k
+	public static int[][] subsetsSumK(int input[], int k) {
+		// Write your code here
+        int start = 0;
+        int end = input.length-1;
+        int[][] jawaab = subsetsSumK(input, k, start, end);
+        return jawaab;
+	}
+
+}