Sort Integers by The Number of 1 Bits

Python solution:

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class Solution:
    def sortByBits(self, arr: List[int]) -> List[int]:
        def countBits(n):
            count = 0
            while n:
                if n & 1:
                    count += 1
                n >>= 1
            return count

        sorted_arr = sorted(arr, key=lambda x: (countBits(x), x))
        return sorted_arr

The code first defines a function called countBits that takes an integer as input and returns the number of bits in the binary representation of the integer.

The sortByBits method takes an array of integers as input and returns the array sorted by the number of bits in the binary representation of the integers. The method first calls the countBits function to get the number of bits in each integer in the array. The method then sorts the array by the number of bits in each integer and then by the value of the integer.

The basic building blocks of the solution are:

  • The countBits function, which takes an integer as input and returns the number of bits in the binary representation of the integer.
  • The sorted function, which takes a list as input and returns a sorted list.
  • The lambda expression, which is used to create a custom sorting function.

The countBits function is a simple function that iterates through the binary representation of the integer and counts the number of bits that are set to 1. The sorted function is a built-in function that takes a list as input and returns a sorted list. The lambda expression is a special expression that can be used to create a custom sorting function.

The sortByBits method uses the countBits function to get the number of bits in each integer in the array. The method then uses the sorted function to sort the array by the number of bits in each integer and then by the value of the integer. The lambda expression is used to create a custom sorting function that sorts the array by the number of bits in each integer and then by the value of the integer.

The basic building blocks of the solution are simple and easy to understand. They are also efficient and can be used to solve a variety of problems.

What is the purpose of using & in the solution?

The & operator is used in the solution to check if a bit is set to 1. The & operator takes two integers as input and returns 1 if the corresponding bits of the two integers are both 1, and 0 otherwise.

In the countBits function, the & operator is used to check if the least significant bit of the integer is set to 1. If the least significant bit is set to 1, then the countBits function increments the counter. The & operator is then used to shift the integer one bit to the right. This process is repeated until the integer is 0.

The & operator is a powerful operator that can be used to perform a variety of operations on integers. In the solution, the & operator is used to count the number of bits in the binary representation of an integer. This is a simple and efficient way to count the number of bits in an integer.

What does »== do in this solution?

The >>== operator in the solution is a bitwise right shift operator. The bitwise right shift operator takes an integer as input and shifts the bits in the integer one bit to the right. The value of the bits that are shifted out are discarded.

In the sortByBits function, the >>== operator is used to shift the integer one bit to the right. This is done to check if the next bit in the binary representation of the integer is set to 1. If the next bit is set to 1, then the countBits function increments the counter.

The >>== operator is a powerful operator that can be used to perform a variety of operations on integers. In the solution, the >>== operator is used to count the number of bits in the binary representation of an integer. This is a simple and efficient way to count the number of bits in an integer.

Here is an example of how the >>== operator works:

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>>> x = 10
>>> x >>= 1
>>> x
5

In this example, the value of x is 10. The >>== operator is used to shift the bits in x one bit to the right. This means that the least significant bit of x is discarded. The value of x is then 5.

The two basic building blocks of the solution is counting the bits in the number and sorting them based on the number of bits in their presentation. Is my understanding correct?

Yes, your understanding is correct. The two basic building blocks of the solution are:

  1. Counting the bits in the number. This is done using the countBits function.
  2. Sorting the numbers based on the number of bits in their binary representation. This is done using the sorted function.

The countBits function is a simple function that iterates through the binary representation of the integer and counts the number of bits that are set to 1. The sorted function is a built-in function that takes a list as input and returns a sorted list.

The sortByBits method uses the countBits function to get the number of bits in each integer in the array. The method then uses the sorted function to sort the array by the number of bits in each integer and then by the value of the integer.

The two basic building blocks of the solution are simple and easy to understand. They are also efficient and can be used to solve a variety of problems.

In addition to the two basic building blocks, the solution also uses the & operator to check if a bit is set to 1 and the >>== operator to shift the integer one bit to the right. These operators are used to count the number of bits in the binary representation of the integer.