地图着色问题又称为“四色问题”，四色问题的内容是：“任何一张地图只用四种颜色就能使具有共同边界的国家着上不同的颜色-map also known as the "four color", the four-color problem is the content : "Anyone with a map of only four colors will be able to have a common border with the country on different colors