2019_GDUT_ newborn Topics I anthology L Codeforces-1260B

topic:

You are given two integers a and b. You may perform any number of operations on them (possibly zero).
During each operation you should choose any positive integer x and set a:=a−x, b:=b−2x or a:=a−2x, b:=b−x. Note that you may choose different values of x in different operations.
Is it possible to make a and b equal to 0 simultaneously?
Your program should answer t independent test cases.
Input
The first line contains one integer t (1≤t≤100) — the number of test cases.

Then the test cases follow, each test case is represented by one line containing two integers a and b for this test case (0≤a,b≤10e9).’
Output
For each test case print the answer to it — YES if it is possible to make a and b equal to 0 simultaneously, and NO otherwise.
You may print every letter in any case you want (so, for example, the strings yEs, yes, Yes and YES will all be recognized as positive answer).
Example
Input
3
6 9
1 1
1 2
Output
YES
NO
YES

Practice: math. x of each operation are equal, i.e. each have a total of 3 x subtracted, so a + b should be a multiple of 3. Assuming all selection operation a: = a-2x, b: = b-x, will find that when a = 2 * b may be 0 when exactly, when a> 2b is in any case can not complete the operation, b> 2a empathy.

Code:

#include<iostream>
#include<cstdio>
using namespace std;

int main()
{
	int T;
	long long a,b;
	cin>>T;
	while (T--)
	{
		cin>>a>>b;
		if ((a+b)%3==0 && (b<=2*a && a<=2*b))
		cout<<"YES"<<endl;
		else cout<<"NO"<<endl;
	}
	return 0;
}