Analog 72
The integrated use of T1 Catalan, the understanding of Cat's not impressive enough.
Then that is for the use of the DP, DP state definition to be selected, try to abandon the superfluous, useless DP, DP to think carefully about the meaning of the definition of an array to choose the appropriate algorithm according to their own definition.
For the definition of DP must not blur, one good tune, and second, will cause confusion in the mind, easy deviation.
Aspects to consider when defining the DP, choose the most suitable for transfer, the most suitable for the optimization of DP start.
Condensing point T3 to FIG no no! ! !
For the determination of the characteristics map, looking after the law can be considered from the direction of bipartite graph bipartite graph this idea is still very important (is the time to review what the biggest matches).
Algorithm as simple as possible, province to province, according to the title selected in the simplest algorithms, such as the right side of the same straight run single-source shortest seek BFS.
Analysis of complexity is still an issue. For those algorithms seemingly "$ n ^ 4 $ $ n ^ 3 $", in fact, does not enumerate so much a correct view of complexity.
Points when the number of edges in different orders, can not be treated equally.