Given two integers A & B, find the number of bits that need to be flipped in B to convert it to A.

flip_bits.cpp

#include <iostream>
using namespace std;

#define ui  uint32_t

ui bit_flips(ui a, ui b) {
    ui flips = 0;
    for(int i = 0; i < 32; ++i, a>>=1, b>>=1)
        if ((a&1) ^ (b&1))
            ++flips;
    return flips;
}

int main() {
    int t;  cin >> t;
    while (t--) {
        ui a, b;    cin >> a >> b;
        cout << bit_flips(a, b) << "\n";
    }
    return 0;
}