SPOJ Solution-Totient Extreme-Solution in C, C++, Java, Python

Input:
2
3
10

Output:
16
1024

#1 Code Example with C++ Programming

Code - C++ Programming

#include <bits/stdc++.h>
#include <limits.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef vector<int> vi;
 
#define MOD (ll)1000000007
#define pb   push_back
#define EPS 1e-9
#define FOR(i,n)  for(int i = 0;i < n; i++)
#define FORE(i,a,b) for(int i = a;i <= b; i++)
#define pi(a)   printf("%d\n", a)
#define all(c)  c.begin(), c.end()
#define tr(container, it)   for(typeof(container.begin()) it = container.begin(); it != container.end(); it++)
#define gc getchar_unlocked
#define sdi(a, b)   si(a);si(b)
#define io ios_base::sync_with_stdio(false);cin.tie(NULL);
#define endl '\n'

template <typename T> T gcd(T a, T b){return (b==0)?a:gcd(b,a%b);}
template <typename T> T lcm(T a, T b){return a*(b/gcd(a,b));}
template <typename T> T mod_exp(T b, T p, T m){T x = 1;while(p){if(p&1)x=(x*b)%m;b=(b*b)%m;p=p>>1;}return x;}
template <typename T> T invFermat(T a, T p){return mod_exp(a, p-2, p);}
template <typename T> T exp(T b, T p){T x = 1;while(p){if(p&1)x=(x*b);b=(b*b);p=p>>1;}return x;}

void si(int &x){
    register int c = gc();
    x = 0;
    int neg = 0;
    for(;((c<48 || c>57) && c != '-');c = gc());
    if(c=='-') {neg=1;c=gc();}
    for(;c>47 && c<58;c = gc()) {x = (x<<1) + (x<<3) + c - 48;}
    if(neg) x=-x;
}

const int MAXN = (int)1e4+5;
ll phi[MAXN+1];

ll prefixSum[MAXN+1];
void precal(){
    for(int i = 1;i <= MAXN; i++){
        phi[i] = i;
    }
    for(int i = 2; i <= MAXN; i++){
        if(phi[i] == i){
            for(int j = i; j <= MAXN; j+=i){
                phi[j] /= i;
                phi[j] *= (i-1);
            }
        }
    }
    prefixSum[0] = 0;
    prefixSum[1] = phi[1];
    for(int i = 2;i <= MAXN; i++){
        prefixSum[i] = phi[i]+prefixSum[i-1];
    }
}



int main(){
    io;
    precal();
    int t;
    cin>>t;
    while(t--){
        int n;
        cin>>n;
        ll ans = 0;
        for(int i = 1;i <= n; i++){
            // cout<<(prefixSum[n]-prefixSum[i-1])<<' '<<phi[i]<<endl;
            ans+=(prefixSum[n])*phi[i];
        }
        cout<<ans<<endl;
    }
    return 0;
}

Copy The Code & Try With Live Editor

Input

Output