codechef MAY18 div2 part of the problem solution

T1

https://www.codechef.com/MAY18B/problems/RD19

Just started zz, it's actually very simple.

Deleting a number will not make gcd smaller, so there are only two cases of 0/1

 

T2

https://www.codechef.com/MAY18B/problems/XORAGN

We can think of the B sequence as a matrix

Then $A(i,j)$ and $A(j,i)$ will cancel

So the answer is $\sum_1^n A(i,i) + A(i,i)$

 

T3

https://www.codechef.com/MAY18B/problems/MTYFRI

The sequence of answers is fixed, so the backhand will replace his smallest with the largest opponent,

Greedy solution, two heaps maintain min max

 

T4

https://www.codechef.com/MAY18B/problems/DBFB

According to the routine, considering the contribution of A and B to the answer, A can only be used as the first item, and B can only be used as the second item.

Count the occurrences of A and B in the Fibonacci sequence

A, B will be enumerated M times, so the answer is multiplied by M at the end

 

T5

A very thoughtful question

It's too late to write a solution.

Abandon the pit. ,

 

current rank

 

By the way Orz zbq 

 

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