This article covers the so-called "min-cost flow" problem, which has many applications for both TopCoder competitors and professional programmers. The article is targeted to readers who are not familiar with the subject, with a focus more on providing a general understanding of the ideas involved rather than heavy theory or technical details for a more in-depth look at this topic, check out the references at the end of this article, in particular [1]. -This article covers the so-called "min-cost flow" problem, which has many applications for both TopCoder competitors and professional programmers. The article is targeted to readers who are not familiar with the subject, with a focus more on providing a general understanding of the ideas involved rather than heavy theory or technical details　for a more in-depth look at this topic, check out the references at the end of this article, in particular [1].