LIS2VN - Another Longest Increasing Subsequence Problem
English | Vietnamese |
Given a sequence of N pairs of integers, find the length of the longest increasing subsequence of it.
An increasing sequence A1..An is a sequence such that for every i < j, Ai < Aj.
A subsequence of a sequence is a sequence that appears in the same relative order, but not necessarily contiguous.
A pair of integers (x1, y1) is less than (x2, y2) if x1 < x2 and y1 < y2.
Input
The first line of input contains an integer N (2 ≤ N ≤ 100000).
The following N lines consist of N pairs of integers (xi, yi) (-109 ≤ xi, yi ≤ 109).
Output
The output contains an integer: the length of the longest increasing subsequence of the given sequence.
Example
Input: 8 1 3 3 2 1 1 4 5 6 3 9 9 8 7 7 6 Output: 3
Original problem: http://www.spoj.com/problems/LIS2/.
Added by: | Race with time |
Date: | 2009-04-13 |
Time limit: | 1s |
Source limit: | 50000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ERL JS-RHINO NODEJS PERL6 VB.NET |
Resource: | Jin Bin - SPOJ |