LITE - Light Switching

Farmer John tries to keep the cows sharp by letting them play with intellectual toys. One of the larger toys is the lights in the barn.  Each of the N (2 <= N <= 100,000) cow stalls conveniently numbered 1..N has a colorful light above it.

At the beginning of the evening, all the lights are off. The cows control the lights with a set of N pushbutton switches that toggle the lights; pushing switch i changes the state of light i from off to on or from on to off.

The cows read and execute a list of M (1 <= M <= 100,000) operations expressed as one of two integers (0 <= operation <= 1).

The first kind of operation (denoted by a 0 command) includes two subsequent integers S_i and E_i (1 <= S_i <= E_i <= N) that indicate a starting switch and ending switch. They execute the operation by pushing each pushbutton from S_i through E_i inclusive exactly once.

The second kind of operation (denoted by a 1 command) asks the cows to count how many lights are on in the range given by two integers S_i and E_i (1 <= S_i <= E_i <= N) which specify the inclusive range in which the cows should count the number of lights that are on.

Help FJ ensure the cows are getting the correct answer by processing the list and producing the proper counts.


Line 1: Two space-separated integers: N and M
Lines 2..M+1: Each line represents an operation with three space-separated integers: operation, S_i, and E_i


Lines 1..number of queries: For each output query, print the count as an integer by itself on a single line.


4 5
0 1 2
0 2 4
1 2 3
0 2 4
1 1 4


hide comments
ABHISHEK004: 2014-01-01 21:57:43

after lots of tle finally acc.. :)
learnt new thing about lazy propogation

Praneeth Reddy: 2013-12-04 17:13:55

TLE for 10th test case???
where is the mistake???
ca anybody explain?

chansiddharth: 2013-02-23 06:55:50

@Sivaraman Nagarajan - ur algo wud never pass . Check the worst case time limit .
This can be solved by Segment tree with lazy propagation !

Sivaraman Nagarajan: 2013-02-20 12:03:17

This is first one freaking me out. I used a simple algo yet got TLE . Plz Help

npsabari: 2012-12-11 18:16:24

<No spoilers in comments>

Last edit: 2012-12-12 07:46:16
:D: 2012-08-24 06:33:52

You can view your solutions and only yours. The issue has already been discussed and it was decided it would hurt the system. There's too much problems with cheating as it is.

Hussain Kara Fallah: 2012-08-24 00:31:04

It's a nice problem .... but the time limit is bad
I optimized and deleted statements to get AC !!
Ugly Optimizations

#1: 2012-08-19 10:38:54

how do i know how many testcases my solution passes? is there any way?

gourav: 2012-08-12 14:19:54

can i view the solutions on spoj ?

guliashvili: 2012-06-10 19:05:54

i had to inline functions not to get TLE.
thats not good time limit bounds..

Added by:Iqram Mahmud
Time limit:0.165s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: OBJC VB.NET
Resource:USACO November 08