二色ボードをトリミングするやつを実装する

[log5r]

こういうの

func trim(_ board: [[Bool]]) -> [[Bool]] {
    let h = board.count, w = board[0].count
    var left = w, right = -1, top = h, bottom = -1
    for r in 0..<h {
        for c in 0..<w where board[r][c] {
            top = min(top, r)
            bottom = max(bottom, r)
            left = min(left, c)
            right = max(right, c)
        }
    }
    var res = [[Bool]]()
    for r in top ... bottom {
        var buf = [Bool]()
        for c in left ... right {
            buf.append(board[r][c])
        }
        res.append(buf)
    }
    return res
}

[log5r]

Array2D側に実装したほうがいい気がする

めっちゃ大変そうだけども