CSP2019 summary
Foreword
It closed two weeks before training camp, since that has been well prepared, and the results ...
Do not know if I have to write hanging points, a point not even hanging, fully prepared to succeed, only 400, or too dishes.
Dy0
Review for a night, playing the game will sleep.
Sleep particularly tasty.
Day1
The early to the examination room, but was told not to test machine, to make up for a nap.
Then opened the subject.
T1
Topic a bit long. After reading it found that water is a problem.
Start from a high place, recursive just fine.
Not knowing how to read usigned long long, hit a quick read.
T2
Feel good fairy look.
Maintaining a stack parentheses represents the root to the current node sequence, with a left parenthesis indicates the right parentheses by -1, and maintaining the prefix of the stack.
Then found that for a point, and set its prefix is x, its contribution to the answer is, from the stack of a number x is equal to the start, the subsequent number is equal to the number of x + 1.
Find the starting point of a segment tree, to find a number with the Chairman of the tree.
Hit half past eleven.
Forgot to turn on the big stack of compiler options how to play, not large sample measured.
T3
No time to think, and took 10 minutes of violence points to leave.
Small mentality collapse.
After the game
Few people seem to get more than 10 T3 score, so it seems to me a very favorable situation?
T2 I think complicated. Segment tree can be replaced with a multiplier; since it is determined starting point, need to find a few in the back also OK, so the President of the trees can be replaced with a bucket.
A too naive.
Afternoon playing games, back for a moment to open a large stack of compiler options.
Day2
T1
I hate to count.
Like a long time, how to remove the index m, we found greater than a maximum number of selected k / 2 only one. It would be much easier. T enumeration not legal, provided f [i] [s1] [s2] s1 represents the time t is selected, the remaining number of programs selected from a number s2 of times, the hand 84 points.
Then we would not optimized.
T2
A look at the data range to know positive solution must be O (n) greedy, but think of how greed.
Want to start \ (n ^ 3 \) of the DP, set f [i] [j] denotes the last paragraph of the first selected, apparently transfer. So desperate to find only 36 points.
F is then found to have a monotonic dimension can be optimized away, more than 28 points.
T3
\ (n ^ 2 \) violence Obviously, whatever the outcome, I also played dotted governance.
The chain is also evident.
Then there is no time.
After the game
T1 may be changed to the state s1-s2, so that you can cut.
In fact, the monotony of the examination room I found that T2 is a positive solution that works.
T3 full binary tree of 20 points is actually relatively simple.
summary
This game should not be too much of a problem, the policy mistakes like that when a NOIP does not appear. In fact, I've could get the points to get over.
But I also exposed the lack of strength. T2 two days have not thought of good practice.
And other write out scores