Personal blog ：Eloi- Still moving forward .

21.11.01 Monday

• Codeforces Round #752 (Div. 2)
  • C. Di-visible Confusion
    The question ： I'll give you a sequence ai If the number is not （i+1） Divisible can be deleted
    Judge whether the series can be completely deleted
    Ideas ：
    – The reasoning question –
    If a number cannot be deleted, then it is right 2 To i+1 Must be divisible
    We can traverse this sequence
    Judge whether each number meets the above requirements
    Satisfaction criterion cout no
    The lesson of blood and tears ： Be sure to read the input data
    wa After an hour, my state of mind collapsed , Only after the game did I know that the input data had not been read .
  • D. Moderate Modular Mode
    – Conclusion question –
    The question ： give x,y Two numbers let you ask n Satisfy n mod x = y mod n
    Conclusion ：
    1. When x=y when n=x
    2. When x>y when n=x+y
    3. When x<y when n=((y/x)*x+y)/2

21.11.02 Tuesday

• Differential restraint system
  • P5960 【 Templates 】 Differential constraint algorithm
    The difference constraint system is actually a set of inequality equations
    Because after its transformation , The form of inequality is very similar to the iterative equation in the shortest path
    We can solve this kind of problem through graph theory
  • P1993 Small K The farm

21.11.3 Wednesday

• P1993 Small K The farm
  – Simple differential constraint system –
  Be careful a=b Can be converted to a-b<=0 And a-b>=0
  a-b=c Empathy

21.11.4 Thursday

• P3275 [SCOI2011] candy
  • Differential restraint system
    a<b Equivalent to a<=b-1
    a>b Equivalent to a>=b+1
    The point to note here is ：
    The feasible solution we get is >=1 Of
    So we should seek the longest way
    And the longest starting path of the super source point is 1
    The drawing method should also be modified consistently
    Details refer to ： Difference constraint

21.11.5 Friday

• Simulated annealing
  • P1337 [JSOI2004] Balance point / To hang up XXX
    As I understand it , Simulated annealing is actually a more rational greed .
    An optimization of mountain climbing algorithm .
    By receiving a temporary worse solution ,
    To get a certain possibility of obtaining the global optimal solution .
    The key lies in the adjustment of parameters .
  • Scope of application of simulated annealing ：
    You can try any question that can be randomized , key word ： Maximum , minimum value .

21.11.6 Saturday

21.11.7 Sunday