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# [BQN](https://mlochbaum.github.io/BQN/), 18 bytes<sup>[SBCS](https://github.com/mlochbaum/BQN/blob/master/commentary/sbcs.bqn)</sup>

```
'A'-¬⊸⌊2×13-˜⌜○↕14
```

[Run online!](https://mlochbaum.github.io/BQN/try.html#code=J0EnLcKs4oq44oyKMsOXMTMty5zijJzil4vihpUxNA==)

This solution computes a table of `c-r`, where `r` is the row number and `c` is the column number, so that the first row is `0 1 2…` and the first column is `0 ¯1 ¯2…`. After this it maps non-positive numbers `0 ¯1 ¯2…` to `A C E…`, and positive ones `1 2…` to `B D…`, using the arithmetic expanded below. BQN's [extension](https://mlochbaum.github.io/BQN/doc/logic.html) of boolean negation `¬` to mean one minus the argument is helpful here.

```
'A'-¬⊸⌊2×13-˜⌜○↕14
         13     14  # Numbers
              ○↕    # Range of each
           -˜⌜      # Subtract-from table    0 ¯1 ¯2 /  1  2
       2×           # Times two              0 ¯2 ¯4 /  2  4
    ¬⊸              # 1 minus, then…         1  3  5 / ¯1 ¯3
      ⌊             # Minimum with original  0 ¯2 ¯4 / ¯1 ¯3
'A'-                # Subtract from 'A'      A  C  E /  B  D
```