Number Complement Problem & Solution
Given a positive integer num, output its complement number.
The complement strategy is to flip the bits of its binary representation.
See the number complement problem on LeetCode.
C++ Solution
#pragma GCC optimize("Ofast")
#pragma GCC optimization("unroll-loops")
static const int _=[](){ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);return 0;}();
class Solution {
public:
int findComplement(int num) {
// Calculates the length of the binary representation of `num`.
int len = log2(num) + 1;
for (int i = 0; i < len; ++i) {
// Flips each bit by using the xor operator with 1.
num ^= (1 << i);
}
return num;
}
};