you are given N and in each line you are given a 3-tuple (xi, yi, zi) that -1e9 <= xi, yi, zi <=1e9 find the LIS of these 3-tuples
a 3-tuple A is greater than B if B1 < A1 and B2 < A2 and B3 < A3
N <= 200000
sample 1 :
5
1 2 3
3 1 2
1 2 2
1 1 1
6 7 8
output :
2
(1, 2, 3)-(6, 7, 8) or (3, 1, 2)-(6, 7, 8) are the LIS
please share your best solution :)