SCORING - Editorial

editorial
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PROBLEM LINK:

Practice
Contest: Division 1
Contest: Division 2
Contest: Division 3
Contest: Division 4

Author: raysh07
Tester: iceknight1093
Editorialist: iceknight1093

DIFFICULTY:

Cakewalk

PREREQUISITES:

None

PROBLEM:

Alice and Bob played a game.
You know that in the end, Alice’s had X more points than Bob; and their total number of points equaled Y.
Find Alice’s and Bob’s scores.

EXPLANATION:

This problem can be solved with some basic algebra.

Let’s use A to denote the number of points Alice had and B to denote the points Bob had.
Then, we know the following pieces of information:

  1. Alice had X points more than Bob.
    This means A = B+X.
  2. Their total points equaled Y.
    This means A+B = Y

Putting the first equation into the second one, we obtain:

Y = A+B = (B+X)+B = 2B+X

Thus,

B = \frac{Y-X}{2}

This uniquely gives us the value of B.
Once B is known, A can be computed as just B+X; and it can be seen to equal \frac{Y+X}{2}.

TIME COMPLEXITY:

\mathcal{O}(1) per testcase.

CODE:

Editorialist's code (PyPy3) 
for _ in range(int(input())):
    x, y = map(int, input().split())
    print((y-x)//2 + x, (y-x)//2)