[LeetCode 191] Number of 1 Bits

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Description

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Given a positive integer n, write a function that returns the number of set bits in its binary representation (also known as the Hamming weight).

Example 1

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• Input: n = 11
• Output: 3
• Explanation: The input binary string 1011 has a total of three set bits.

Example 2

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• Input: n = 128
• Output: 1
• Explanation: The input binary string 10000000 has a total of one set bit.

Example 3

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• Input: n = 2147483645
• Output: 30
• Explanation: The input binary string 1111111111111111111111111111101 has a total of thirty set bits.

Constraints

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• 1 <= n <= 2^31 - 1

Code

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내 제출

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class Solution {
    public int hammingWeight(int n) {
        int result = 0; // 결과 값 변수

        while (n > 0) {
             result += n % 2;
             n /= 2;
        }
        return result;
    }
}

Runtime	Memory
0 ms	40.6 MB

다른 풀이

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class Solution {
    public int hammingWeight(int n) {
        int c=0;
        while(n>0){
            n=n&(n-1);
            c++;
        }
        return c;
    }
}

Reference

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