May Long 2019 Solutions Sketches

editorial
25

Seriously brother math god!! @l_returns

3 Likes
26

thanks but I’m far away from being math god… :slight_smile:

2 Likes
27

How to be good in maths in competitive programming?

28

I really don’t know… I love maths since 8th standard… I just did maths from 8th to 10th… :joy:

2 Likes
29

Same quetstion. :stuck_out_tongue: :stuck_out_tongue: :stuck_out_tongue: :stuck_out_tongue:

1 Like
30

I_sees… !!! _/_

31

And there is usually a good deal of difference between CF and CC editorials.

1 Like
32

what ??
…

33

Sir in question when to build roads, is it allow to build restaurant on the road

34

Just thought of this and thought it explains the formula pretty well.
a + b + a * b = (a + 1) * (b + 1) - 1.
Now, for ((a, b) , c) , we can substitute the above result as ((a + 1) * (b + 1) - 1, c)
Expanding this we get (a + 1) * (b + 1) * (c + 1) - 1. Hence, no matter how many operations you do and in what order you do, you will get (a + 1) * (b + 1) * (c + 1) * … - 1. Since the numbers here go from 1 to N, our answer become (1 + 1) * ( 2 + 1) * (3 + 1) * … * (N + 1) - 1. This is essentially (N + 1)! - 1.

Hope this helps.

2 Likes
35

How u have expanded (a+1)*(b+1)-1 ,c ?? @gameface_123

1 Like
36

Let (a + 1) * (b + 1) - 1 = d
Then, (d, c) = (d + 1) * ( c + 1) - 1
But d = ( a + 1 ) * ( b + 1) - 1 .
Hence, (d + 1) = ( a + 1) * ( b + 1)
Hence, (d, c) = (a + 1) * (b + 1) * (c + 1) - 1

1 Like
37

Please provide the link for your editorials.

2 Likes
38

404 :stuck_out_tongue::joy::joy::joy:
Post must be at least 20 characters

1 Like
39

@vijju123 @I_returns can anyone plz find the error in this code for MATCHES problem
thanks in advance!!..

#include <math.h>
#include<bits/stdc++.h>
#define ll long long
using namespace std;

int maximum(int a,int b)
{
if(a>b)
return a;
else
return b;
}

int minimum(int a,int b)
{
if(a>b)
return b;
else
return a;
}

int main()
{
ll t;
cin>>t;
while(t–)
{
ll i,n,m,a,b,k;

   cin>>n>>m;

   i=0;

   while(n!=0&&m!=0)
   {
       
      i++;
      a=minimum(n,m);

      if(a==m)
      {
         n=n%m;

      }
      else
      {
          m=m%n;
      }

   }
   if((i-1)%2==0)
   {
       cout<<"Ari"<<endl;
   }
   else
   {
       cout<<"Rich"<<endl;
   }

}
}

40

Where are the editorials for May Long Challenge 2019??! @admin
Can you pls send the link…

41

Here is the editorial:-

42

Here it is:-Unofficial Editorial for ADAROOKS2-MAY-2019-LONG-CHALLENGE

43

not available yet
to check it yourself enter ‘may19’ in the search box on the page at

44

feels like this has been forgotten now. thats why editorial should be done before even contest starts.

3 Likes