Directed Acyclic Graph

Given a directed graph, output YES if it is acyclic, and NO otherwise.

Input

As usual.
N ≤ 1000.

Output

YES or NO.

Sample Input

3
0 1 0 
0 0 1
1 0 0

Sample Output

NO

Sample Input 2

3
0 1 0
0 0 1
0 0 0

Sample Output 2

YES

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Point Value: 10
Time Limit: 2.00s
Memory Limit: 16M
Added: Jun 28, 2013

Problem Types: [Show]

Languages Allowed:
C++03, PAS, C, HASK, ASM, RUBY, PYTH2, JAVA, PHP, SCM, CAML, PERL, C#, C++11, PYTH3

Comments (Search)

ultblad1 on Jun 10, 2015 - 11:52:35 pm UTC Input clarification
  • (0/0)
First number is the number of edges, but for each edge, what does the third number stand for?

wgma00 on Jun 11, 2015 - 1:07:43 am UTC Re: Input clarification
  • (2/0)
This is the correct interpretation of the input.
http://wcipeg.com/wiki/Graph_theory#Adjacency_matrix

jargon on Jun 11, 2015 - 3:35:39 am UTC Re: Input clarification
  • (1/0)
As usual -> see graph2p1.