Std.FenwickTree

11 public declarations

• add&Std.FenwickTree.FenwickTree -> Int -> Int -> Option[Std.FenwickTree.FenwickTree]

  Adds `delta` to the 1-based element at `index` in O(log n) time.

  fn
• createInt -> Std.FenwickTree.FenwickTree

  Allocates a zero-initialized Fenwick tree for sequence length `elementCount`.

  fn
• FenwickTree

  A low-level Binary Indexed Tree for O(log n) prefix sums and point updates.

  type
• findPrefix&Std.FenwickTree.FenwickTree -> Int -> Option[Int]

  Finds the smallest 1-based index whose prefix sum is >= `targetSum` in O(log n) time.

  fn
• fromArray&Array[Int] -> Std.FenwickTree.FenwickTree

  Builds a Fenwick tree in strict O(n) linear time from an array of initial values.

  fn
• get&Std.FenwickTree.FenwickTree -> Int -> Option[Int]

  Retrieves the single value at 1-based `index` in O(log n) time.

  fn
• prefixSum&Std.FenwickTree.FenwickTree -> Int -> Option[Int]

  Computes the prefix sum up to 1-based `index` in O(log n) time.

  fn
• rangeSum&Std.FenwickTree.FenwickTree -> Int -> Int -> Option[Int]

  Computes the range sum [left, right] inclusive in O(log n) time.

  fn
• set&Std.FenwickTree.FenwickTree -> Int -> Int -> Option[Std.FenwickTree.FenwickTree]

  Sets the 1-based element at `index` to `value`.

  fn
• size&Std.FenwickTree.FenwickTree -> Int

  Returns the number of elements in the tree.

  fn
• toArray&Std.FenwickTree.FenwickTree -> Array[Int]

  Materializes the tree values into a standard 0-indexed array.

  fn