Number of 1 Bits.cpp

/* Leet Code */
/* Title - Number of 1 Bits */
/* Created By - Akash Modak */
/* Date - 17/10/2020 */

// 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 above, the input represents the signed integer. -3.
// Follow up: If this function is called many times, how would you optimize it?

 

// 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.

class Solution {
public:
    int hammingWeight(uint32_t n) {
        int ans = 0;
        while(n>0){
            if(n&1)
              ans++;
            n = n>>1;
        }
        return ans;
    }
};