SPCU - Gopu and Validity of Arrangement
N persons are standing in a line. Height of each person is between 1 and N and height of each person is distinct.
You are given an array A where A[i] denotes how many persons are there before the i_th person having heights greater than the height of the ith person. For a person i, all the persons from 1 to i - 1 are considered to be before him. eg, For person 2, person 1 is considered before him.
You have to find out whether this array can be valid for some arrangement of persons. If you can uniquely do so then output "YES" Otherwise output "NO".
Input
First line contains T : number of test cases. (1 <= T <= 20).
For each test First line contains an integer n. (1 <= N <= 10^5)
Next line contains n space separated integers denoting A[i]. (0 <= A[i] <= N)
Output
For each test case, output "YES" or "NO" according to answer.
Example
Input: 2
2
0 1
2
1 1 Output: YES
NO
Explanation
For the first test case, [2, 1] is a valid case, First person has height 2, second person has height 1.
For the second test case, no valid test case exists.
hide comments
sk128:
2021-04-02 06:50:25
I humbly request the problem setters to mention that YES , Yes and yes will be treated differently.
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vivek_prime:
2021-01-22 17:41:29
Easy question
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mrdevesh_00:
2019-12-18 23:00:05
VERY EASY AC IN ONE GO!!!! |
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wolfie10:
2019-05-17 20:48:58
the logic is fairly simple and straightforward..test cases are deceptive.. :P |
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silentknight16:
2019-02-18 18:47:04
Tricky ;) |
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be1035016:
2018-01-18 16:32:41
easy 1 |
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kotal_kahn:
2017-07-22 17:47:39
why it is showing the wrong answer even though my logic is correct
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Shivam Gupta:
2017-03-14 12:29:13
Don't think too much, its a trick question |
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gajalchouhan:
2017-03-08 09:03:15
please anyone can give me some another example when the print is coming " no".
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Anuj Arora:
2016-08-17 22:27:26
Move this to tutorial |
Added by: | praveen123 |
Date: | 2014-01-08 |
Time limit: | 2s |
Source limit: | 50000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ASM64 |
Resource: | IITK ACA CSE online judge |