CF1878C.Vasilije in Cacak
普及/提高-
通过率:0%
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题目描述
Aca and Milovan, two fellow competitive programmers, decided to give Vasilije a problem to test his skills.
Vasilije is given three positive integers: n , k , and x , and he has to determine if he can choose k distinct integers between 1 and n , such that their sum is equal to x .
Since Vasilije is now in the weirdest city in Serbia where Aca and Milovan live, Cacak, the problem seems weird to him. So he needs your help with this problem.
输入格式
The first line contains a single integer t ( 1≤t≤104 ) — the number of test cases.
The only line of each test case contains three integers n , k and x ( 1≤n≤2⋅105 , 1≤k≤n , 1≤x≤4⋅1010 ) — the maximum element he can choose, the number of elements he can choose and the sum he has to reach.
Note that the sum of n over all test cases may exceed 2⋅105 .
输出格式
For each test case output one line: "YES", if it is possible to choose k distinct integers between 1 and n , such that their sum is equal to x , and "NO", if it isn't.
You can output the answer in any case (for example, the strings "yEs", "yes", "Yes", and "YES" will be recognized as a positive answer).
输入输出样例
输入#1
12 5 3 10 5 3 3 10 10 55 6 5 20 2 1 26 187856 87856 2609202300 200000 190000 19000000000 28 5 2004 2 2 2006 9 6 40 47202 32455 613407217 185977 145541 15770805980
输出#1
YES NO YES YES NO NO YES NO NO NO YES YES
说明/提示
In the first test case n=5, k=3, x=10 , so we can choose the numbers: 2 , 3 , 5 , whose sum is 10 , so the answer is "YES".
In the second test case n=5, k=3, x=3 , there is no three numbers which satisfies the condition, so the answer is "NO". It can be shown that there are no three numbers whose sum is 3 .