leetcode 日经贴，Cpp code -Count Primes

Count Primes

class Solution {public:    int countPrimes(int n) {        if (n <= 1) {            return 0;        }        bitset< 5000001> notpr;        vector<int> primes;        //primes.reserve(60000);        for (int i = 2; i < n; ++i) {            if (!notpr[i]) {                primes.push_back(i);            }            for (int j = 0; j < primes.size() && primes[j] * i < n; ++j) {                int k = primes[j] * i;                notpr[k] = 1;                if (i % primes[j] == 0) {                    break;                }            }        }        return primes.size();    }};