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
mohit2598: 2019-07-10 16:20:18

Anyone going wrong at 10th test case.. Here is what is happening..
Corner case is when you are going to mark a lazy node again to be lazy.
So, while marking the "child nodes" of a node lazy,, check if they are previously set to lazy.. If yes, then mark them unlazy or 0,, else mark them lazy or 1..

dkkv0000: 2019-05-14 22:17:24

after 3 hrs AC :) my first lazy propagation

amantu_amir: 2019-04-03 23:18:50

AC after trying about a week,,,
Same as "Multiple of 3".

shivam077: 2019-03-22 08:31:16

cin,cout -> TLE
cin,cout with fast input output -> TLE
printf,scanf -> Correct Ans

abhimanyu_1998: 2019-03-10 05:52:01

AC in one go

vinayakii: 2019-01-15 08:29:58

tle in java

shan61916: 2018-12-25 15:59:02

Everyone, who just copy pasted FLIPCOIN from codechef, keep in mind that FLIPCOIN had a zero(0) based indexing while this question has a 1 based indexing.

yaseenmollik: 2018-11-15 00:29:21

AC in 2 go -_- . Got TLE on first submission just for using cin, cout! Then used fast I/O and got accepted. Btw, it is my first problem using Lazy Propagation.

Last edit: 2018-11-15 00:31:00
pola_pawaad59: 2018-11-01 17:43:08

can anyone help me with this problem?

atharva_sarage: 2018-10-28 20:38:54

easy peasy lemon squeezy

Added by:Iqram Mahmud
Time limit:1s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: OBJC VB.NET
Resource:USACO November 08