Submission #32268032

---

Source Code Expand

#include <bits/stdc++.h>
template<typename T>
inline T chkmin(T& x, const T& y){if (x > y) x = y; return x;}
template<typename T>
inline T chkmax(T& x, const T& y){if (x < y) x = y; return x;}
using namespace std;
typedef long long ll;
const int NN = 1919810, N = 1e6;
int n, L, notprime[NN], phi[NN];
vector<int> plist;
inline void linear_sieve(int n)
{
    notprime[1] = true; phi[1] = 1;
    for (int i=2; i<=n; i++)
    {
        if (!notprime[i]){plist.emplace_back(i); phi[i] = i-1;}
        for (auto x : plist)
        {
            int now = i*x;
            if (now > n) break;
            notprime[now] = true;
            if (!(i%x)){phi[now] = phi[i] * x; break;}
            phi[now] = phi[i] * phi[x];
		}
	}
}
ll F(int l, int n)
{
	ll ans = 0;
	for (int i=l; i*i<=n; i++) ans += phi[i] * (n / (i * i));
	return ans;
}
int main()
{
	scanf("%d", &n); L = sqrt(n); linear_sieve(L+1); 
	printf("%lld\n", F(1, n) + F(2, n));
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:35:7: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   35 |  scanf("%d", &n); L = sqrt(n); linear_sieve(L+1);
      |  ~~~~~^~~~~~~~~~

Judge Result