Programmer Think

Spy network Title Link: ybt gold navigation 3-5-5 / luogu P1262 General idea of the topic There are some people, some of them, you can catch them, and then there is a fee. Then after a person is caught, he can help you catch some people. Ask if you can catch everyone with the minimum cost. If you can output the minimum cost, otherwise output ...

Title portal General idea of the topic Give you an undirected graph. Each edge in the graph is blue or red. Each time you select a point, you will reverse the color of the edge connected to the point (red turns blue and blue turns red). The scheme of finding the minimum number of steps will make the color of all edges the same. thinking ...