7.7
1、
DP first array inheritance tree, the complexity of the optimization. Trie branch number is O (n). dsu on tree.
Tree DP f [x] [min (SIZE, m)], the complexity O (nm), the combination proved.
2、
There is the state tree DP side.
The midpoint of the diameter of the tree only, can be used to enumerate the diameter of the tree.
3、
Fractional Programming dinkelbach optimization complexity.
Meaning of the questions: 100 * 100 digital matrix, to find sub-matrix and meet the digital / maximum circumference.
4、
The meaning of problems: a sequence of N strings of required sub-divided into two sequences, such that each sub-sequence before a string is a sequence of sub (or substring)
Linear complexity.
5、
The meaning of problems: a given length n sequence of positive integers A, can be any number in the sequence number is reversed, and asked for the number of reverse 1, 2, ..., m the number of programs.
For a [i]> a [j], only to change a [i] will reverse the impact of this pair is not right.
Optimization backpack use bitset.