solve 4948

problems/4948/21300875_4948.cpp

@@ -0,0 +1,33 @@
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+bool isprime(int n) {
+  if(n < 2) return false;
+  for(int i=2; i*i<=n; i++){
+    if (n%i == 0)
+      return false;
+  }
+  return true;
+}
+
+int main() {
+  int N = 0;
+  vector<int> v;
+  while(1){
+    int cnt = 0;
+    cin >> N;
+    if(N==0) break;
+    for(int i=N+1;i<=2*N;i++){
+      if(isprime(i)) cnt++;
+    }
+    v.push_back(cnt);
+  }
+
+  for(int i=0;i<v.size();i++){
+    cout << v[i] << endl;
+  }
+
+  return 0;
+}