Codeforces Round 834 (Div. 3) |
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Finished |
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?
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.
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).
53 133 1 41 113 31 4 22 14 35 61 2 3 4 5
YES NO YES NO YES
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.
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