code-bitmask-approach2.cpp

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 * Code for the book "DAILY 43: Algorithmic Problems for Coding Interviews: Easy level, C++ edition"
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#include <iostream>
#include <cstdint>
#include <bitset>

uint32_t reverseBits(uint32_t n) {
    n = (n >> 16) | (n << 16);
    n = ((n & 0b11111111000000001111111100000000) >> 8) | ((n & 0b00000000111111110000000011111111) << 8);
    n = ((n & 0b11110000111100001111000011110000) >> 4) | ((n & 0b00001111000011110000111100001111) << 4);
    n = ((n & 0b11001100110011001100110011001100) >> 2) | ((n & 0b00110011001100110011001100110011) << 2);
    n = ((n & 0b10101010101010101010101010101010) >> 1) | ((n & 0b01010101010101010101010101010101) << 1);
    return n;
}

int main() {
    uint32_t num = 43261596; // Example input (binary: 00000010100101000001111010011100)
    uint32_t reversed = reverseBits(num);
    std::cout << "Original: " << num << " (" << std::bitset<32>(num) << ")" << std::endl;
    std::cout << "Reversed: " << reversed << " (" << std::bitset<32>(reversed) << ")" << std::endl;

    return 0;
}