I solved 3 questions and the rating increased slightly.
- It’s not clear to me that I only solved 3 questions, but those 3 questions were solved in 18 minutes, so I guess it’s a light blue performance?
- AtCoder problems, C is unknown difficulty.
- Exactly the same as the official explanation.
- Potential question, “How do you come up with that?”
- Solve for small specific values, like X=5, D=2, etc.
- While the absolute value of X is greater than D, it moves in the direction of decreasing
- When small, it oscillates across the origin.
- The number of cycles is 2, so look at the remainder of the number of cycles remaining divided by 2. python
def solve(X, K, D):
X = abs(X)
a = X // D
if a >= K:
return X - K * D
r = X % D
K -= a
if K % 2 == 0:
return r
else:
return D - r
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