Count set bits (Hamming weight) for an integer

Question

Accepted Answer

Approach Loop while n != 0, increment count, n &= n-1. Each iteration removes one set bit. Java Solution int hammingWeight(int n) { int c = 0; while (n != 0) { c++; n &= (n - 1); } return c; } Complexity Time O(k) bits set Space O(1) Interview tip: Brian Kernighan's algorithm — classic bit trick interview question.