<PREV Problem:
NEXT>
Solved by 125 users: ...
UserDateAttemptTimeCMSC
pav23 aug 2009Ruby3500.13221 
mishik08 sep 2007C++700.11233 
Igor_Kvasov22 dec 2003FPC3?.??233 
RustamDz22 mar 2007FPC200.03243 
WsemirZ23 mar 2008Kylix700.03249 
mishik11 sep 2007C++900.07251 
WsemirZ23 mar 2008Kylix500.03252 
WsemirZ23 mar 2008Kylix600.03252 
WsemirZ23 mar 2008Kylix100.03254 
WsemirZ23 mar 2008Kylix200.03254 
sema21 aug 2008C200.05257 
tomek20 feb 2006C++100.02263 
Shurik28 oct 2006Kylix200.11264 
Ra16bit15 mar 2008FPC100.04268 
PetrovSergey12 oct 2004FPC1?.??271 
Languages
C++
78
FPC
23
C
15
Kylix
9
Java
3
Ruby
1
Python
1
 > 
 > 
 > 
 > 
 > 
 > 
 > 
 > 
 > 
 > 

Defragmentation

Time limit = 5 seconds

You are taking part in the development of a "New Generation" operating system and the NG file system. In this file system all disk space is divided into N clusters of the equal sizes, numbered by integers from 1 to N. Each file occupies one or more clusters in arbitrary areas of the disk. All clusters that are not occupied by files are considered to be free. A file can be read from the disk in the fastest way, if all its clusters are situated in the successive disk clusters in the natural order.

Rotation of the disk with constant speed implies that various amounts of time are needed for accessing its clusters. Therefore, reading of clusters located near the beginning of the disk performs faster than reading of the ones located near its ending.

Thus, all files are numbered beforehand by integers from 1 to K in the order of descending frequency of access. Under the optimal placing of the files on the disk the file number 1 will occupy clusters 1,2, ... S1 , the file number 2 will occupy clusters S1+1, S1+2, ... , S1+S2 and so on (here Si is the number of clusters which the i-th file occupies). In order to place the files on the disk in the optimal way cluster-moving operations are executed. One cluster-moving operation includes reading of one occupied cluster from the disk to the memory and writing its contents to some free cluster. After that the first of them is declared free, and the second one is declared occupied.

Your goal is to place the files on the disk in the optimal way by executing the minimal possible number of cluster-moving operations.

Input The first line of the input file contains two integers N and K separated by a space (1 ≤ K, N ≤ 10000). Then K lines follow, each of them describes one file. The description of the i-th file starts with the integer Si that represents the number of clusters in the i-th file (1 ≤ SiN). Then Si integers follow separated by spaces, which indicate the cluster numbers of this file on the disk in the natural order.

All cluster numbers in the input file are different and there is always at least one free cluster on the disk.

Output Your program should write to the output number of cluster-moving operation and any sequence of cluster-moving operations that are needed to place the files on the disk in the optimal way. Two integers Pj and Qj separated by a single space should represent each cluster-moving operation. Pj gives the cluster number that the data should be moved FROM and Qj gives the cluster number that this data should be moved TO.

The number of cluster-moving operations executed should be as small as possible. If the files on the disk are already placed in the optimal way the output should contain only the string "No optimization needed".

Input#1
20 3
4 2 3 11 12
1 7
3 18 5 10

Output#1
2 1
3 2
11 3
12 4
18 6
10 8
5 20
7 5
20 7

Author:

<PREV | Problem set | Search related messages | NEXT>


© acm.mipt DevGroup
The page was generated in 190ms

SW soft NIX
ID = 75.101.220.230