diff --git "a/ts\"" "b/ts\""
deleted file mode 100644
index daddada971db..000000000000
--- "a/ts\""
+++ /dev/null
@@ -1,179 +0,0 @@
-diff --git a/src/main/java/com/thealgorithms/datastructures/trees/FenwickTree.java b/src/main/java/com/thealgorithms/datastructures/trees/FenwickTree.java
-index 5378a01..be8a92e 100644
---- a/src/main/java/com/thealgorithms/datastructures/trees/FenwickTree.java
-+++ b/src/main/java/com/thealgorithms/datastructures/trees/FenwickTree.java
-@@ -1,29 +1,33 @@
- package com.thealgorithms.datastructures.trees;
- 
-+/** Fenwick Tree for point updates and prefix-sum queries in O(log n). */
- public class FenwickTree {
- 
--    private int n;
--    private int[] fenTree;
-+    private final int n;
-+    private final int[] fenTree;
- 
--    /* Constructor which takes the size of the array as a parameter */
-+    /** Creates a Fenwick tree with n elements, all initialized to zero. */
-     public FenwickTree(int n) {
-+        if (n < 0) {
-+            throw new IllegalArgumentException("Size must be non-negative");
-+        }
-         this.n = n;
-         this.fenTree = new int[n + 1];
-     }
- 
--    /* A function which will add the element val at index i*/
-+    /** Adds val to the element at index i. */
-     public void update(int i, int val) {
--        // As index starts from 0, increment the index by 1
--        i += 1;
-+        checkIndex(i);
-+        i += 1; // Convert to the internal 1-based index
-         while (i <= n) {
-             fenTree[i] += val;
-             i += i & (-i);
-         }
-     }
- 
--    /* A function which will return the cumulative sum from index 1 to index i*/
-+    /** Returns the sum of elements from index 0 to i. */
-     public int query(int i) {
--        // As index starts from 0, increment the index by 1
-+        checkIndex(i);
-         i += 1;
-         int cumSum = 0;
-         while (i > 0) {
-@@ -32,4 +36,11 @@ public class FenwickTree {
-         }
-         return cumSum;
-     }
-+
-+    // Check that the index is within the valid range.
-+    private void checkIndex(int i) {
-+        if (i < 0 || i >= n) {
-+            throw new IndexOutOfBoundsException("Index " + i + " out of bounds for size " + n);
-+        }
-+    }
- }
-diff --git a/src/test/java/com/thealgorithms/datastructures/trees/FenwickTree.java b/src/test/java/com/thealgorithms/datastructures/trees/FenwickTree.java
-new file mode 100644
-index 0000000..47ef568
---- /dev/null
-+++ b/src/test/java/com/thealgorithms/datastructures/trees/FenwickTree.java
-@@ -0,0 +1,115 @@
-+package com.thealgorithms.datastructures.trees;
-+
-+import static org.junit.jupiter.api.Assertions.assertEquals;
-+import static org.junit.jupiter.api.Assertions.assertThrows;
-+
-+import java.util.Random;
-+import org.junit.jupiter.api.Test;
-+
-+class FenwickTreeTest {
-+
-+    @Test
-+    void queryOnFreshTreeReturnsZero() {
-+        FenwickTree tree = new FenwickTree(5);
-+        for (int i = 0; i < 5; i++) {
-+            assertEquals(0, tree.query(i));
-+        }
-+    }
-+
-+    @Test
-+    void singleElementTree() {
-+        FenwickTree tree = new FenwickTree(1);
-+        tree.update(0, 7);
-+        assertEquals(7, tree.query(0));
-+    }
-+
-+    @Test
-+    void prefixSumsAfterUpdates() {
-+        FenwickTree tree = new FenwickTree(5);
-+        int[] values = {3, 2, -1, 6, 5};
-+        for (int i = 0; i < values.length; i++) {
-+            tree.update(i, values[i]);
-+        }
-+        assertEquals(3, tree.query(0));
-+        assertEquals(5, tree.query(1));
-+        assertEquals(4, tree.query(2));
-+        assertEquals(10, tree.query(3));
-+        assertEquals(15, tree.query(4));
-+    }
-+
-+    @Test
-+    void repeatedUpdatesOnSameIndexAccumulate() {
-+        FenwickTree tree = new FenwickTree(4);
-+        tree.update(2, 5);
-+        tree.update(2, 3);
-+        tree.update(2, -2);
-+        assertEquals(0, tree.query(1));
-+        assertEquals(6, tree.query(2));
-+        assertEquals(6, tree.query(3));
-+    }
-+
-+    @Test
-+    void negativeValues() {
-+        FenwickTree tree = new FenwickTree(3);
-+        tree.update(0, -4);
-+        tree.update(1, -6);
-+        tree.update(2, 10);
-+        assertEquals(-4, tree.query(0));
-+        assertEquals(-10, tree.query(1));
-+        assertEquals(0, tree.query(2));
-+    }
-+
-+    @Test
-+    void nonPowerOfTwoSize() {
-+        int size = 13;
-+        FenwickTree tree = new FenwickTree(size);
-+        for (int i = 0; i < size; i++) {
-+            tree.update(i, 1);
-+        }
-+        for (int i = 0; i < size; i++) {
-+            assertEquals(i + 1, tree.query(i));
-+        }
-+    }
-+
-+    @Test
-+    void matchesNaivePrefixSumOnRandomData() {
-+        Random random = new Random(42);
-+        int size = 100;
-+        FenwickTree tree = new FenwickTree(size);
-+        int[] naive = new int[size];
-+
-+        for (int step = 0; step < 500; step++) {
-+            int index = random.nextInt(size);
-+            int delta = random.nextInt(21) - 10;
-+            tree.update(index, delta);
-+            naive[index] += delta;
-+        }
-+
-+        int running = 0;
-+        for (int i = 0; i < size; i++) {
-+            running += naive[i];
-+            assertEquals(running, tree.query(i), "Mismatch at index " + i);
-+        }
-+    }
-+
-+    @Test
-+    void zeroSizeTreeRejectsAnyIndex() {
-+        FenwickTree tree = new FenwickTree(0);
-+        assertThrows(IndexOutOfBoundsException.class, () -> tree.update(0, 1));
-+        assertThrows(IndexOutOfBoundsException.class, () -> tree.query(0));
-+    }
-+
-+    @Test
-+    void negativeSizeThrows() {
-+        assertThrows(IllegalArgumentException.class, () -> new FenwickTree(-1));
-+    }
-+
-+    @Test
-+    void outOfBoundsIndicesThrow() {
-+        FenwickTree tree = new FenwickTree(5);
-+        assertThrows(IndexOutOfBoundsException.class, () -> tree.update(-1, 1));
-+        assertThrows(IndexOutOfBoundsException.class, () -> tree.update(5, 1));
-+        assertThrows(IndexOutOfBoundsException.class, () -> tree.query(-1));
-+        assertThrows(IndexOutOfBoundsException.class, () -> tree.query(5));
-+    }
-+}