Leetcode 191. Number of 1 Bits. Python

191. Number of 1 Bits

Write a function that takes an unsigned integer and returns the number of '1' bits it has (also known as the Hamming weight).

Note:

Note that in some languages, such as Java, there is no unsigned integer type. In this case, the input will be given as a signed integer type. It should not affect your implementation, as the integer's internal binary representation is the same, whether it is signed or unsigned.
In Java, the compiler represents the signed integers using 2's complement notation. Therefore, in Example 3, the input represents the signed integer. -3.

Example 1:

Input: n = 00000000000000000000000000001011
Output: 3
Explanation: The input binary string 00000000000000000000000000001011 has a total of three '1' bits.

Example 2:

Input: n = 00000000000000000000000010000000
Output: 1
Explanation: The input binary string 00000000000000000000000010000000 has a total of one '1' bit.

Example 3:

Input: n = 11111111111111111111111111111101
Output: 31
Explanation: The input binary string 11111111111111111111111111111101 has a total of thirty one '1' bits.

Constraints:

The input must be a binary string of length 32.

class Solution:
    def hammingWeight(self, n: int) -> int:
        
        #trick 1
        
        ans = 0
        while n:
            ans += n % 2
            n = n >> 1
        return ans
    
    
        # trick 2
        
        ans = 0
        while n:
            n &=(n-1)
            ans += 1
        return ans

Explained :

Comments

May-6 2020 Challenge

6. Majority Element Given an array of size n , find the majority element. The majority element is the element that appears more than ⌊ n/2 ⌋ times. You may assume that the array is non-empty and the majority element always exist in the array. Example 1: Input: [3,2,3] Output: 3 Example 2: Input: [2,2,1,1,1,2,2] Output: 2 Solution in Java class Solution { public int majorityElement(int[] num) { int m = num[0], cnt= 1; for (int i = 1; i < num.length; i++) { if (cnt == 0) { m= num[i]; cnt = 1; } else if (num[i] == m) { cnt++; } else cnt--; } return m;...

Leetcode 190. Reverse Bits. Python. Bit Manipulation

190 . Reverse Bits Reverse bits of a given 32 bits unsigned integer. Note: Note that in some languages, such as Java, there is no unsigned integer type. In this case, both input and output will be given as a signed integer type. They should not affect your implementation, as the integer's internal binary representation is the same, whether it is signed or unsigned. In Java, the compiler represents the signed integers using 2's complement notation . Therefore, in Example 2 above, the input represents the signed integer -3 and the output represents the signed integer -1073741825 . Example 1: Input: n = 00000010100101000001111010011100 Output: 964176192 (00111001011110000010100101000000) Explanation: The input binary string 00000010100101000001111010011100 represents the unsigned integer 43261596, so return 964176192 which its binary representation is 00111001011110000010100101000000 . Example 2: Input: n = 11111111111111111111...

Longest Substring Without Repeating Characters - Leetcode 3 - Python

Given a string s, find the length of the longest substring without repeating characters. class Solution: def lengthOfLongestSubstring(self, s: str) -> int: charSet = set() left = 0 ans = 0 for right in range(len(s)): while s[right] in charSet: charSet.remove(s[left]) left+=1 charSet.add(s[right]) ans = max(ans, right-left+1) return ans Explained :

LEETCODE SOLUTIONS

Search This Blog