#C. ARC106C - Solutions

    Type: Default 1000ms 256MiB

ARC106C - Solutions

You cannot submit for this problem because the contest is ended. You can click "Open in Problem Set" to view this problem in normal mode.

Problem Statement

Two segments [L1:R1] and [L2:R2] are said to intersect when L1R2 and L2R1 holds.

Consider the following problem P:

Input: N segments [L1:R1],,[LN:RN]
       L1,L2,,LN,R1,R2,,RN are pairwise distinct.
Output: the maximum number of segments that can be chosen so that no two of them intersect.

Takahashi has implemented a program that works as follows:

Sort the given segments in the increasing order of Ri and let the result be [Lp1:Rp1],[Lp2:Rp2],,[LpN:RpN].
For each i=1,2,,N, do the following:
  Choose [Lpi:Rpi] if it intersects with none of the segments chosen so far.
Print the number of chosen segments.

Aoki, on the other hand, has implemented a program that works as follows:

Sort the given segments in the increasing order of Li and let the result be [Lp1:Rp1],[Lp2:Rp2],,[LpN:RpN].
For each i=1,2,,N, do the following:
  Choose [Lpi:Rpi] if it intersects with none of the segments chosen so far.
Print the number of chosen segments.

Given are integers N and M. Construct an input for the problem P, consisting of N segments, such that the following holds:

(The value printed by Takahashi’s program)(The value printed by Aoki’s program)=M

image

Sample Input 1

5 1

Sample Output 1

1 10
8 12
13 20
11 14
2 4

image

Sample Input 2

10 -10

Sample Output 2

-1

ARC106

Not Attended
Status
Done
Rule
IOI
Problem
6
Start at
2023-7-5 8:15
End at
2023-7-5 10:15
Duration
2 hour(s)
Host
Partic.
13