A13290. Sum of Odd Integers
编程题
普及/提高-
知识点
题目描述
You are given two integers $n$ and $k$ . Your task is to find if $n$ can be represented as a sum of $k$ distinct positive odd (not divisible by $2$ ) integers or not.
You have to answer $t$ independent test cases.
You have to answer $t$ independent test cases.
输入格式
The first line of the input contains one integer $t$ ( $1 \le t \le 10^5$ ) — the number of test cases.
The next $t$ lines describe test cases. The only line of the test case contains two integers $n$ and $k$ ( $1 \le n, k \le 10^7$ ).
The next $t$ lines describe test cases. The only line of the test case contains two integers $n$ and $k$ ( $1 \le n, k \le 10^7$ ).
输出格式
For each test case, print the answer — "YES" (without quotes) if $n$ can be represented as a sum of $k$ distinct positive odd (not divisible by $2$ ) integers and "NO" otherwise.
输入输出样例
输入 #1
6 3 1 4 2 10 3 10 2 16 4 16 5
输出 #1
YES YES NO YES YES NO
说明/提示
In the first test case, you can represent $3$ as $3$ .
In the second test case, the only way to represent $4$ is $1+3$ .
In the third test case, you cannot represent $10$ as the sum of three distinct positive odd integers.
In the fourth test case, you can represent $10$ as $3+7$ , for example.
In the fifth test case, you can represent $16$ as $1+3+5+7$ .
In the sixth test case, you cannot represent $16$ as the sum of five distinct positive odd integers.
In the second test case, the only way to represent $4$ is $1+3$ .
In the third test case, you cannot represent $10$ as the sum of three distinct positive odd integers.
In the fourth test case, you can represent $10$ as $3+7$ , for example.
In the fifth test case, you can represent $16$ as $1+3+5+7$ .
In the sixth test case, you cannot represent $16$ as the sum of five distinct positive odd integers.