PROBLEM LINK:
Practice
Contest: Division 1
Contest: Division 2
Contest: Division 3
Contest: Division 4
Author: S. Manuj Nanthan
Tester: Harris Leung
Editorialist: Nishank Suresh
DIFFICULTY:
823
PREREQUISITES:
None
PROBLEM:
Given two numbers A and B, in one move you can choose an integer d and add d to A while subtracting d from B, or vice versa. Can A and B be made equal?
EXPLANATION:
A and B can be made equal if and only if they have the same parity, i.e, either they are both even or they are both odd.
Proof
- Suppose they have the same parity. Let A \leq B. Then, choose d = \frac{B-A}{2} and they become equal.
- Suppose they have different parities. Then, after choosing any d and performing an operation, they will still have different parities. In particular, they can never be made equal, since it will always be the case the one of A and B is even while the other is odd.
TIME COMPLEXITY
\mathcal{O}(1) per test case.
CODE:
Editorialist's code (Python)
for _ in range(int(input())):
a, b = map(int, input().split())
print('yes' if a%2 == b%2 else 'no')