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https://github.com/TheAlgorithms/C-Plus-Plus.git
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70 lines
1.8 KiB
C++
70 lines
1.8 KiB
C++
/**
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* @file
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* @brief Program to Count set bits in an integer
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*
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* @details
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* Time Complexity :- O(log n)
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* Space complexity :- O(1)
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* @author [Swastika Gupta](https://github.com/swastyy)
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*/
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#include <cassert> /// for assert
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#include <iostream> /// for io operations
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#include <vector> /// for std::vector
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/**
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* @namespace bit_manipulation
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* @brief bit set counting algorithm
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*/
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namespace bit_manipulation {
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/**
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* @namespace bitCount
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* @brief Functions for counting set bits in binary representation of a number
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*/
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namespace bitCount {
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/**
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* @brief The main function implements set bit count
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* @param n is the number whose set bit will be counted
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* @returns count , the number set bit in binary representation of n
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*/
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std::uint64_t countSetBits(unsigned int n) {
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int count = 0; // "count" variable is used to count number of 1's in binary representation of the number
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while (n!=0) {
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count += n&1;
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n=n>>1; // n=n/2
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}
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return count;
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}
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} // namespace bitCount
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} // namespace bit_manipulation
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/**
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* @brief Test implementations
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* @returns void
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*/
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static void test() {
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// n = 4 return 1
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assert(bit_manipulation::bitCount::countSetBits(4)==1);
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// n = 6 return 2
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assert(bit_manipulation::bitCount::countSetBits(6)==2);
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// n = 13 return 3
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assert(bit_manipulation::bitCount::countSetBits(13)==3);
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// n = 9 return 2
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assert(bit_manipulation::bitCount::countSetBits(9)==2);
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// n = 15 return 4
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assert(bit_manipulation::bitCount::countSetBits(15)==4);
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// n = 25 return 3
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assert(bit_manipulation::bitCount::countSetBits(25)==3);
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std::cout << "All test cases passed" << std::endl;
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}
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/**
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* @brief Main function
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* @returns 0 on exit
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*/
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int main() {
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test(); // execute the test
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return 0;
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}
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