NICEDAY - The day of the competitors

The International Olympiad in Informatics is coming and the leaders of the Vietnamese Team have to choose the best contestants all over the country. Fortunately, the leaders could choose the members of the team among N very good contestants, numbered from 1 to N (3 ≤ N ≤ 100000). In order to select the best contestants the leaders organized three competitions. Each of the N contestants took part in all three competitions and there were no two contestants with equal results on any of the competitions. We say that contestant А is better than another contestant В when А is ranked before В in all of the competitions. A contestant A is said to be excellent if no other contestant is better than A. The leaders of the Vietnamese Team would like to know the number of excellent contestants.


First line of the input contains an integer t (1 ≤ t ≤ 10), equal to the number of test cases. Then descriptions of t test cases follow. First line of description contains the number of competitors N . Each of the next N lines describes one competitor and contains integer numbers ai, bi, ci (1 ≤ ai, bi, ci ≤ N ) separated by spaces, the order of i-th competitor's ranking in the first competition , the second competition and the third competition.


For each test case in the input your program should output the number of excellent contestants in one line.

Note: Because the input is too large so we have 4 input files and the total time limit is 4s (not 1s).


1 2 3
2 3 1
3 1 2


hide comments
Medo: 2017-04-18 09:49:48

It is worth checking how to solve this problem by Sweeps even if you solved it using a Tree structure.

Last edit: 2017-04-18 09:50:06
shubham: 2017-03-27 13:26:25

This problem will reduced to counting inversion problem after sorting

saiful130104: 2017-01-23 17:33:42

if inputs are like this....
1 1 1
2 2 2
3 3 3
4 4 4
5 5 5
then what will be the output ?
is it 1?

Last edit: 2017-01-23 22:12:42
Mohammad Asif: 2016-08-20 17:40:04

The problem statement is horrible and very confusing. I think the problem setter meant sth else..
The way I see it , the answer should be '0'.

Nguyen Cuong: 2016-04-05 07:12:55

NKTEAM got 100, TLE here :v

UPDATE: got TLE because read input format like NKTEAM :v

Last edit: 2016-04-05 07:27:22
minhthai: 2016-02-16 14:44:43

any tips for BIT in java to pass ?

vijay77794: 2016-01-04 20:12:42

done with help :(.............. but learnt a lot.....:)

(Tjandra Satria Gunawan)(曾毅昆): 2015-08-19 15:01:58

Awesome problem (^_^) think asymmetrically to solve this :)

sai krishna: 2015-03-27 04:02:27

cant understand the qusetion itself
can any one please explain

californiagurl: 2015-01-31 12:44:34

any tricky testcase?

Added by:Nguyen Minh Hieu
Time limit:0.109s
Source limit:10000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ERL JS-RHINO NODEJS PERL6 VB.NET
Resource:Base on a problem from BOI