KURUK14  GENIE SEQUENCE
A Genie Sequence is a sequence in which every element indicates the number of elements present before or after it. Given an array of numbers, find whether you can form a Genie sequence or not.
Input
First line contains a single integer T, the number of test cases. It is followed by T cases each of which contains two lines. First line of each test case contains a single integer N. The next line contains N integers separated by a single space.
Output
For each test case output a single line containing "YES
" (without quotes) if it is possible to form a genie sequence or "NO
" (without quotes) if it is not possible.
Constraints
1 <= T <= 20
2 <= N <= 1000
1 <= ai <= 1000
Example
Input: 1 4 1 3 3 2 Output: YES
Explanation for the test case:
The Genie sequence is {3, 1, 2, 3}. The first element '3' in the sequence indicates that three numbers are after it, the 2nd element '1' indicates that one number if before it, the 3rd element '2' indicates that two elements are before it and the last element indicates that three elements are before it. So the answer is YES.
hide comments
Piyush Kumar:
20150308 09:02:41
Can anybody provide some tricky test cases ?


Daksh:
20150124 21:13:42
AC in one go easy1 :) 

:.Mohib.::
20141220 11:37:49
Easy....:) 

Aditya Joshi:
20141017 17:58:31
One pass O(n) algorithm fails time limit with Java. Had to use C++ to get an AC. Time limit is too strict for Java. 

KAI:
20140926 22:02:29
took some time but ac in 1 go :) 

a7b:
20140822 16:25:37
Can't find error in my solution but is giving wrong answer


WA:
20140806 22:08:46
easy if you get the trick 

P_Quantum:
20140703 14:17:09
easy!! 

:
20140621 12:41:34
Can anyone provide more test cases! Last edit: 20140621 12:42:43 

Divyank Duvedi:
20140523 20:36:55
Easy...A/C in one go!!

Added by:  785227 
Date:  20140131 
Time limit:  0.100s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  C CSHARP C++ 4.3.2 CPP C99 JAVA PERL PYTHON PYTHON3 
Resource:  Kurukshetra Onsite Programming Contest 