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Lost Permutation

1000ms 262144K

Description:

A sequence of $$$n$$$ numbers is called a permutation if it contains all integers from $$$1$$$ to $$$n$$$ exactly once. For example, the sequences [$$$3, 1, 4, 2$$$], [$$$1$$$] and [$$$2,1$$$] are permutations, but [$$$1,2,1$$$], [$$$0,1$$$] and [$$$1,3,4$$$] — are not.

Polycarp lost his favorite permutation and found only some of its elements — the numbers $$$b_1, b_2, \dots b_m$$$. He is sure that the sum of the lost elements equals $$$s$$$.

Determine whether one or more numbers can be appended to the given sequence $$$b_1, b_2, \dots b_m$$$ such that the sum of the added numbers equals $$$s$$$, and the resulting new array is a permutation?

Input:

The first line of input contains a single integer $$$t$$$ ($$$1 \le t \le 100$$$) —the number of test cases.

Then the descriptions of the test cases follow.

The first line of each test set contains two integers $$$m$$$ and $$$s$$$ ($$$1 \le m \le 50$$$, $$$1 \le s \le 1000$$$)—-the number of found elements and the sum of forgotten numbers.

The second line of each test set contains $$$m$$$ different integers $$$b_1, b_2 \dots b_m$$$ ($$$1 \le b_i \le 50$$$) — the elements Polycarp managed to find.

Output:

Print $$$t$$$ lines, each of which is the answer to the corresponding test set. Print as the answer YES if you can append several elements to the array $$$b$$$, that their sum equals $$$s$$$ and the result will be a permutation. Output NO otherwise.

You can output the answer in any case (for example, yEs, yes, Yes and YES will be recognized as positive answer).

Sample Input:

5
3 13
3 1 4
1 1
1
3 3
1 4 2
2 1
4 3
5 6
1 2 3 4 5

Sample Output:

YES
NO
YES
NO
YES

Note:

In the test case of the example, $$$m=3, s=13, b=[3,1,4]$$$. You can append to $$$b$$$ the numbers $$$6,2,5$$$, the sum of which is $$$6+2+5=13$$$. Note that the final array will become $$$[3,1,4,6,2,5]$$$, which is a permutation.

In the second test case of the example, $$$m=1, s=1, b=[1]$$$. You cannot append one or more numbers to $$$[1]$$$ such that their sum equals $$$1$$$ and the result is a permutation.

In the third test case of the example, $$$m=3, s=3, b=[1,4,2]$$$. You can append the number $$$3$$$ to $$$b$$$. Note that the resulting array will be $$$[1,4,2,3]$$$, which is a permutation.

Informação

Codeforces

Provedor Codeforces

Código CF1759B

Tags

math

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Datas 09/05/2023 10:33:45

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