Reconstruction.split_column: def of bend-edit-distance@0.2.2.0
Import: import bend-edit-distance@0.2.2.0/src/Reconstruction.bend as Reconstruction
Lines 146-160 of bend-edit-distance@0.2.2.0/src/Reconstruction.bend: https://jend.leeeet.dev/read.txt?path=bend-edit-distance@0.2.2.0/src/Reconstruction.bend&start_line=146&end_line=160

import Base

# Forward[j] + reverse[n-j] is the cost through the midpoint at column j.
# Strict comparison keeps the first minimum; this is our deterministic split
# policy and is deliberately separate from upstream Hirschberg compatibility.
def split_column(forward: List<U32>, backward: List<U32>, +index: Nat,
                  +best_index: Nat, +best_score: U32) -> Nat:
  match forward backward:
    case Nil{} _:
      best_index
    case _ Nil{}:
      best_index
    case a <> at b <> bt:
      +score = U32.add(a, b)
      +next = split_update(index, score, best_index, best_score,
        U32.is_lt(score, best_score))
      split_column(at, bt, 1n+index, split_index(next), split_score(next))

Uses (8):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.add
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.is_lt
  https://jend.leeeet.dev/definition.txt?path=bend-edit-distance@0.2.2.0/src/Reconstruction.bend&name=split_index
  https://jend.leeeet.dev/definition.txt?path=bend-edit-distance@0.2.2.0/src/Reconstruction.bend&name=split_score
  https://jend.leeeet.dev/definition.txt?path=bend-edit-distance@0.2.2.0/src/Reconstruction.bend&name=split_update