search for: value_colors

Hi~I'm new to R. I'm following these two tutorials to make a tree map, but the color scale isn't quite what I wanted. For map of the market, the color scale starts from 0(red) to max(green), what I wanted is 0(Green)-1(Red)-max(green). What's the easiest way to achieve this kind of divergent color scale? How shall I make my own palette and use it in the map.market or tree map