Lua对角线遍历：行列交替的斜向扫描

local function diagWalk(g)
    local m, n = #g, #g[1]
    local out = {}
    local s = 0
    while s <= m + n - 2 do
        if s % 2 == 0 then
            for i = math.min(m, s + 1),
                math.max(1, s + 2 - n), -1 do
                out[#out + 1] = g[i][s + 2 - i]
            end
        else
            for i = math.max(1, s + 2 - n),
                math.min(m, s + 1) do
                out[#out + 1] = g[i][s + 2 - i]
            end
        end
        s = s + 1
    end
    return out
end

local grid = {{1, 2, 3, 4},
    {5, 6, 7, 8}, {9, 10, 11, 12}}
local p = getplayerbyname("diag01")
sendmsg(p, 1, "斜向序 "
    .. table.concat(diagWalk(grid), ","))