Question:
On the board Ivy wrote down all integers from to , inclusive.
In an operation, she does the following:
- pick two numbers and on the board, erase them, and in their place write the numbers and . (Here denotes rounding down to the nearest integer).
What is the minimum number of operations Ivy needs to make all numbers on the board equal ? We have a proof that this is always possible.
The first line contains an integer () — the number of test cases.
The only line of each test case contains two integers and ().
For each test case, output a single integer — the minimum number of operations needed to make all numbers on the board equal .
41 32 4199999 20000019 84
5 6 36 263
In the first test case, we can perform operations as follows:
My think:
At first, I thought it was a simple simulation problem: calculate the number of times x when the smallest
number divided by 3 equals 0, and then the answer would be x * 2 plus the number of remaining times when
the left number divided by 3 equals 0. However, this approach is incorrect.
By utilizing the characteristics of exponential growth and performing some simple
calculations, we can quickly determine the minimum number of operations within a given range.
This method has a low time complexity and can efficiently handle large input ranges.
Code:
1 | import math |
1 | def min_operations_to_zero(n): |