Function snake

internal/diff.ts:274–294

(
    k: number,
    A: T[],
    B: T[],
    slide?: FarthestPoint,
    down?: FarthestPoint,
  )

  let ptr = 0;

  function snake<T>(
    k: number,
    A: T[],
    B: T[],
    slide?: FarthestPoint,
    down?: FarthestPoint,
  ): FarthestPoint {
    const M = A.length;
    const N = B.length;
    const fp = createFp(k, M, routes, diffTypesPtrOffset, ptr, slide, down);
    ptr = fp.id;
    while (fp.y + k < M && fp.y < N && A[fp.y + k] === B[fp.y]) {
      const prev = fp.id;
      ptr++;
      fp.id = ptr;
      fp.y += 1;
      routes[ptr] = prev;
      routes[ptr + diffTypesPtrOffset] = COMMON;
    }
    return fp;
  }

  let currentFp = fp[delta + offset];
  assertFp(currentFp);