(LeetCode OJ) Number of 1 Bits (191]

(LeetCode OJ) Number of 1 Bits (191]

191. Number of 1 Bits

QuestionTotal Accepted: 65438 Total Submissions: 172909 Difficulty: Easy

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

For example, the 32-bit integer '11' has binary representation00000000000000000000000000001011, So the function shocould return 3.

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Special thanks to @ ts for adding this problem and creating all test cases.

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// Clear thinking: first, this number is a positive integer, and the question is clear. // certain situations: as long as this number is not 0, it will have 1 // reduce the leftmost binary 1 in each loop --- "n = n & n-1 // For example, if there are 5 1 s, it will be cyclically 5 times (reduce 5 times) class Solution {public: int hammingWeight (uint32_t n) {int cnt = 0; while (n) {cnt ++; n = n & n-1; // reduce the leftmost 1} return cnt ;}} in the binary ;}};