CF1759B.Lost Permutation
普及/提高-
通过率:0%
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题目描述
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 b1,b2,…bm . 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 b1,b2,…bm such that the sum of the added numbers equals s , and the resulting new array is a permutation?
输入格式
The first line of input contains a single integer t ( 1≤t≤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≤m≤50 , 1≤s≤1000 )—-the number of found elements and the sum of forgotten numbers.
The second line of each test set contains m different integers b1,b2…bm ( 1≤bi≤50 ) — the elements Polycarp managed to find.
输出格式
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).
输入输出样例
输入#1
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
输出#1
YES NO YES NO YES
说明/提示
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.