2022/3/22 examination summary

Time arrangement

There are classes in the morning, so we play replay in the afternoon

1:00~1:20

I feel very uncomfortable after reading the question
The first two questions are bit operations ,T3 It's probability
I don't know why , The first two questions look very good FWT The appearance of
Sudden death

1:20~1:50

Yes T1,T2 The violence of
Expected score 30pts

1:50~2:10

Think of the natural number pairs mentioned in the math competition class 3 The law of remainder
Pushed for a while , Found for binary , In the mold 3 In the sense of
Adding an odd number is equivalent to adding two , Adding an even digit is equivalent to adding one
By the way
The rest seems to need only classified discussion

2:10~2:30

It's easy to implement
After adjusting it for a while, it was photographed

2:30~3:00

T2 Directly put FWT It's on your face
But I can only write m=1
After writing, there is no idea left

3:00~3:10

Want to write T3 The search
It's too difficult to write, so I gave it up

3:10~3:40

consider dp, At first, consider the interval dp
After finding that the transfer has nothing to do with the left endpoint , Change to linear dp
Complexity $O(n^4)$

3:40~4:20

Find that the transition can be changed to prefix and
Complexity becomes $O(n^3)$
Can get 60 branch
Worry about space explosion , So the card space is blocked

4:20~4:40

Measured T1 Large sample of
the reason being that spj, So I wrote a checker
Found a place to explode int 了
It's no problem to change