# leetcode 201. Bitwise AND of Numbers Range

## 题目描述

Given a range [m, n] where 0 <= m <= n <= 2147483647, return the bitwise AND
of all numbers in this range, inclusive.

Example 1:

``````Input: [5,7]
Output: 4``````

Example 2:

``````Input: [0,1]
Output: 0``````

Tags: Bit Manipulation

Difficulty: Medium



# leetcode 231. Power of Two

## 题目描述

Given an integer, write a function to determine if it is a power of two.

Example 1:

``````Input: 1
Output: true
Explanation: 20 = 1``````

Example 2:

``````Input: 16
Output: true
Explanation: 24 = 16``````

Example 3:

``````Input: 218
Output: false``````

Tags: Math, Bit Manipulation

Difficulty: Easy



# leetcode 762. Prime Number of Set Bits in Binary Representation

## 题目描述

Given two integers `L` and `R`, find the count of numbers in the range ```[L, R]``` (inclusive) having a prime number of set bits in their binary
representation.

(Recall that the number of set bits an integer has is the number of `1`s
present when written in binary. For example, `21` written in binary is `10101`
which has 3 set bits. Also, 1 is not a prime.)

Example 1:

``````Input: L = 6, R = 10
Output: 4
Explanation:
6 -> 110 (2 set bits, 2 is prime)
7 -> 111 (3 set bits, 3 is prime)
9 -> 1001 (2 set bits , 2 is prime)
10->1010 (2 set bits , 2 is prime)``````

Example 2:

``````Input: L = 10, R = 15
Output: 5
Explanation:
10 -> 1010 (2 set bits, 2 is prime)
11 -> 1011 (3 set bits, 3 is prime)
12 -> 1100 (2 set bits, 2 is prime)
13 -> 1101 (3 set bits, 3 is prime)
14 -> 1110 (3 set bits, 3 is prime)
15 -> 1111 (4 set bits, 4 is not prime)``````

Note:

1. `L, R` will be integers `L <= R` in the range `[1, 10^6]`.
2. `R - L` will be at most 10000.

Tags: Bit Manipulation

Difficulty: Easy

# leetcode 461. Hamming Distance

## 题目描述

The Hamming distance between
two integers is the number of positions at which the corresponding bits are
different.

Given two integers `x` and `y`, calculate the Hamming distance.

Note:
0 ≤ `x`, `y` < 231.

Example:

``````Input: x = 1, y = 4

Output: 2

Explanation:
1   (0 0 0 1)
4   (0 1 0 0)
↑   ↑

The above arrows point to positions where the corresponding bits are different.``````

Tags: Bit Manipulation

Difficulty: Easy

# leetcode 268. Missing Number

## 题目描述

Given an array containing n distinct numbers taken from `0, 1, 2, ..., n`,
find the one that is missing from the array.

Example 1:

``````Input: [3,0,1]
Output: 2``````

Example 2:

``````Input: [9,6,4,2,3,5,7,0,1]
Output: 8``````

Note :
Your algorithm should run in linear runtime complexity. Could you implement it
using only constant extra space complexity?

Tags: Array, Math, Bit Manipulation

Difficulty: Easy

# leetcode 78. Subsets

## 题目描述

Given a set of distinct integers, nums , return all possible subsets
(the power set).

Note: The solution set must not contain duplicate subsets.

Example:

``````Input: nums = [1,2,3]
Output:
[
,
,
,
[1,2,3],
[1,3],
[2,3],
[1,2],
[]
]``````

Tags: Array, Backtracking, Bit Manipulation

Difficulty: Medium

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