30 lines
905 B
C++
30 lines
905 B
C++
#include <iostream>
|
|
|
|
/**
|
|
* 762. Prime Number of Set Bits in Binary Representation
|
|
* Given two integers left and right, return the count of numbers in the inclusive range [left, right] having a prime number of set bits in their binary representation.
|
|
* Recall that the number of set bits an integer has is the number of 1's present when written in binary.
|
|
* For example, 21 written in binary is 10101, which has 3 set bits.
|
|
*/
|
|
|
|
class Solution {
|
|
private:
|
|
static inline const int IS_PRIME[32] = {0, 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1};
|
|
public:
|
|
static int countPrimeSetBits(int left, int right) {
|
|
int ret = 0;
|
|
for (int i = left; i <= right; ++i) {
|
|
int x = 0;
|
|
for (int n = i; n; n >>= 1)
|
|
x += n & 1;
|
|
ret += IS_PRIME[x];
|
|
}
|
|
return ret;
|
|
}
|
|
};
|
|
|
|
int main() {
|
|
std::printf("%d\n", Solution::countPrimeSetBits(6, 10));
|
|
return 0;
|
|
}
|