Lua蛇形填数：往返交替的行序填充

local function zigzag(n)
    local m = {}
    local v = 1
    for i = 1, n do
        m[i] = {}
        if i % 2 == 1 then
            for j = 1, n do m[i][j] = v; v = v + 1 end
        else
            for j = n, 1, -1 do m[i][j] = v; v = v + 1 end
        end
    end
    return m
end

local p = getplayerbyname("zig01")
local m = zigzag(4)
for i = 1, 4 do
    sendmsg(p, 1, table.concat(m[i], ","))
end