SumsOfPerfectPowers.cpp

/**
 *                                   ____
 *       ____ ___  ____ ________  __/ __/
 *      / __ `__ \/ __ `/ ___/ / / / /_
 *     / / / / / / /_/ / /  / /_/ / __/
 *    /_/ /_/ /_/\__,_/_/   \__,_/_/
 *
 *    @link : https://the-redback.com
 */

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef unsigned long long llu;

#define ft first
#define sd second
// #define mp        make_pair
#define pb(x)     push_back(x)
#define all(x)    x.begin(), x.end()
#define allr(x)   x.rbegin(), x.rend()
#define mem(a, b) memset(a, b, sizeof(a))
#define meminf(a) memset(a, 126, sizeof(a))
#define inf       1e11
#define eps       1e-9
#define mod       1000000007
#define NN        5000100

// cout << setfill('0') << setw(3) << a << endl;
// cout << fixed << setprecision(20) << a << endl;
ll flag = 0;
bool mp[NN], mpp[NN];

ll power(ll n, ll x) {
    ll ret = 1;
    while (x > 0) {
        ret *= n;
        x--;
    }
    return ret;
}

struct SumsOfPerfectPowers {
    int howMany(int low, int up) {
        ll ret = 0;
        vector<ll> v;
        v.clear();
        ll i, j, k, l;
        mem(mp, 0);
        mem(mpp, 0);
        mp[0] = 1;
        mp[1] = 1;
        v.pb(0);
        v.pb(1);
        ll N = sqrt(up);
        for (i = 2; i <= N + 1; i++) {
            j = 2;
            while (1) {
                ll temp = power(i, j);
                if (temp > up) break;
                if (mp[temp] == 0) v.pb(temp);
                mp[temp] = 1;
                j++;
            }
            // cout<<i<<"\n";
        }
        sort(all(v));
        // cout<<"done\n";
        for (i = 0; i < v.size(); i++) {
            for (j = 0; j < v.size(); j++) {
                k = v[i] + v[j];
                if (k >= low && k <= up) {
                    if (mpp[k] == 0) {
                        mpp[k] = 1;
                        ret++;
                    }
                }
            }
        }
        return ret;
    }

    // BEGIN CUT HERE
public:
    void run_test(int Case) {
        if ((Case == -1) || (Case == 0)) test_case_0();
        if ((Case == -1) || (Case == 1)) test_case_1();
        if ((Case == -1) || (Case == 2)) test_case_2();
        if ((Case == -1) || (Case == 3)) test_case_3();
        if ((Case == -1) || (Case == 4)) test_case_4();
    }

private:
    template <typename T>
    string print_array(const vector<T>& V) {
        ostringstream os;
        os << "{ ";
        for (typename vector<T>::const_iterator iter = V.begin(); iter != V.end(); ++iter) os << '\"' << *iter << "\",";
        os << " }";
        return os.str();
    }
    void verify_case(int Case, const int& Expected, const int& Received) {
        cerr << "Test Case #" << Case << "...";
        if (Expected == Received)
            cerr << "PASSED" << endl;
        else {
            cerr << "FAILED" << endl;
            cerr << "\tExpected: \"" << Expected << '\"' << endl;
            cerr << "\tReceived: \"" << Received << '\"' << endl;
        }
    }
    void test_case_0() {
        int Arg0 = 0;
        int Arg1 = 1;
        int Arg2 = 2;
        verify_case(0, Arg2, howMany(Arg0, Arg1));
    }
    void test_case_1() {
        int Arg0 = 5;
        int Arg1 = 6;
        int Arg2 = 1;
        verify_case(1, Arg2, howMany(Arg0, Arg1));
    }
    void test_case_2() {
        int Arg0 = 25;
        int Arg1 = 30;
        int Arg2 = 5;
        verify_case(2, Arg2, howMany(Arg0, Arg1));
    }
    void test_case_3() {
        int Arg0 = 103;
        int Arg1 = 103;
        int Arg2 = 0;
        verify_case(3, Arg2, howMany(Arg0, Arg1));
    }
    void test_case_4() {
        int Arg0 = 1;
        int Arg1 = 100000;
        int Arg2 = 33604;
        verify_case(4, Arg2, howMany(Arg0, Arg1));
    }

    // END CUT HERE
};

// BEGIN CUT HERE
int main() {
    SumsOfPerfectPowers z;
    // int x=z.howMany(1,4999999);
    // cout<<x;
    ___test.run_test(-1);
    int gbase;
    cin >> gbase;  // erase this line if you are not using dev-cpp! :)
    return 0;
}
// END CUT HERE