Fixed sieves

Author: fredbr

math/linear_sieve.cpp

@@ -2,7 +2,7 @@
 
 using namespace std;
 
-const int maxn = 10101010;
+const int maxn = 101010101;
 
 int lp[maxn];
 
@@ -33,4 +33,5 @@ int main()
 	for (int p : ans)
 		cout << p << " ";
 	cout << "\n";
+	// cout << ans.size() << "\n";
 }

math/sieve.cpp

@@ -6,21 +6,27 @@ const int maxn = 101010101;
 
 char s[maxn];
 // bitset<maxn> s;
-vector<int> primes;
 
-
-void init()
+vector<int> sieve(int n)
 {
-	for (int i = 2; i*i < maxn; i++)
+	for (int i = 2; i*i <= n; i++)
 		if (!s[i]) 
-			for (int j = i*i; j < maxn; j += i)
+			for (int j = i*i; j <= n; j += i)
 				s[j] = 1;
 
-	for (int i = 2; i < maxn; i++)
+	vector<int> primes;
+	for (int i = 2; i <= n; i++)
 		if (!s[i]) primes.push_back(i);
+
+	return primes;
 }
 
 int main()
 {
-	init();
+	int n;
+	cin >> n;
+
+	auto ans = sieve(n);
+
+	cout << ans.size() << "\n";
 }