<>A
1,2019<X<Y
2,2019^2, X^2, Y^2 Constitute arithmetic sequence
Satisfying conditions X and Y There may be many situations , Please give me X+Y Value of , And make X+Y As small as possible .
<>B
2019 It can be decomposed into several prime numbers which are different in pairs , How many different decomposition schemes are there ?
be careful ： The decomposition scheme does not consider the order , as 2+2017=2019 and 2017+2=2019 It belongs to the same scheme .
（dp knapsack problem , It doesn't have to be the sum of two primes , probably 3 number ,4 The sum of the numbers is equal to 2019
, It's just that each pair of primes is different , I got the wrong idea in the game , It means adding two numbers , So it's written 1. I'll try it after the game dfs I wrote it , But it didn't work out for four hours ）
<>C
7×7 square , It's divided into two parts , Each part is connected , After the right half is flipped and rotated, so is after the splicing 7×7,
How many segmentation methods are there
<>D
There is one 7X7 The grid of . The coordinates of the top left corner of the grid are (0,0), The coordinates of the lower right corner are (7,7).
Find the number of paths satisfying the following conditions ：
1, Both the starting point and the ending point are (0,0)
2, Path does not self intersect
3, Path length is not greater than 12
4, For each vertex , There are four directions to go up, down, left and right , But you can't cross the border .
for example , Route in the picture , Top left vertex （0,0）, The route length is 10
<>E
Yes 1 The minimum number of divisors is 1（1）, The minimum number with two divisors is 2（1,2）……
Yes n The minimum number of divisors is Sn
S1=1 （1）
S2=2 （1 2）
S3=4 （1 2 4）
S4=6 （1 2 3 6）
seek S100
<>F
The title is given two strings S and T, ensure S The length of is not less than T Length of , Ask at least to modify S How many characters are there , Can make T become S Subsequence of .（dp）
sample input 1：
ABCDABCD
AABCX
sample output 1：
1
sample input 2：
ABCDABCD
XAAD
sample output 2：
2
sample input 3：
XBBBBBAC
ACC
sample output 3：
2
<>H puzzle game （ I can't remember. There may be mistakes ）
Three rings of matches , Outer ring 12 root , kick-off circle 8 root , Inner ring 4 Follow , All in all 12 root , yellow 8 green 4
* Three turns can rotate one unit clockwise at the same time
* Three turns can rotate one unit counter clockwise at the same time
* The top three rounds of matches can be rotated in a specific order （ External , in , within —> in , within , External ）, No other way
First line input n, Representatives need to judge n group .
Three circles are represented by three strings ,R red ,Y yellow ,G green
Can you replace the outer ring with red , All yellow in the middle , Inner ring all green . Can output Yes, otherwise No
sample input ：
2
RGRRRRRRRRRR
YRYYYYYY
GYGG
RRGRRRRRRRRR
YYYYYYYY
GGRG
sample output ：
Yes
No
<>G Permutation number
For a number in a sequence , If the number is larger than the number on both sides or smaller than the number on both sides , We call this number a turning point in the sequence .
If a sequence has t Turning point , We call this sequence t+1 Tone sequence .
Give two positive integers n,k. Seeking in 1~n In the full permutation of , How many sequences are there k Tone sequence .
（ Write your own full permutation code + prune ）
Data range ：
about 10% Data for ,0<=k,n<=10
about 20% Data for ,0<=k,n<=20
about 30% Data for ,0<=k,n<=100
about 100% Data for ,0<=k,n<=1000
Enter a description ：
Two positive integers n,k.
Output description ：
answer , An integer .
sample input ：
4 2
sample output ：
12
<>I The Eighth Wonder
There is a river , Along the side of the river lives a tribe . This one letter tribe has n Strongholds , Number from left to right 1~n.
Tribal people sometimes build buildings in a stronghold , Each building has its own value . in limine , There are no buildings in every stronghold , The values are all 0. If a new building is built in a stronghold of an existing building , Then the new building will replace the old one （ The old buildings disappeared ）.
There are two operations C and Q：
1,C x y, It means in the stronghold x Building a value for y The architecture of .
2,Q x y, The inquiry is in the stronghold x~y between （ include x,y） In the architecture of , What is the value of the eighth most valuable building .
( Line segment tree , Chairman tree )
Enter a description ：
first line , Two positive integers n and k, Represents the number of sites and operations .
Next k That's ok , One action per line .
Output description ：
For all Q operation , Output the corresponding value of the eighth largest building .
sample input ：
10 14
C 1 5
C 2 4
C 3 7
C 4 6
C 5 5
C 6 1
C 7 8
Q 1 10
C 8 3
C 9 6
C 10 3
Q 1 9
C 6 10
Q 1 10
sample output ：
0
3
4
<>J Burning Scepter
Technology