Gas tank

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;

ll val(ll A, ll B){
    return A*A*B + B*B*A;
}

ll dA(ll A, ll B){
    return 2*B*A+B*B;
}

ll dB(ll A, ll B){
    return 2*B*A+A*A;
}

int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);

    ull N;
    cin >> N;

    if(N == 0){
        cout << "0 0\n";
        return 0;
    }

    ull bA=0, bB=0;
    ll bS=(unsigned)(-1);

    ll a = 1;
    bool anygood = true;
    while(exchange(anygood, false)){
        anygood = false;
        for(ll b=1; b<=a; b++){
            // cout << "this: " << a << " " << b << "\n";
            ll v = val(a, b);
            ll e = N - v;
            // cout << a << " " << b << " " << e << "\n";
            if(e >= 0 && e < bS){
                bA = a;
                bB = b;
                bS = e;
            }
            anygood |= (e >= 0);
        }
        a ++;
    }

    cout << bA << " " << bB << "\n";
    // cout << bA << " " << bB << " " << val(bA, bB) << endl;
}

Test 1

Verdict: ACCEPTED

Test 2

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Test 3

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Test 4

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Test 5

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Test 6

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Test 7

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Test 8

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Test 9

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Test 10

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Test 11

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Test 12

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Test 15

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Test 18

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Test 19

Verdict: ACCEPTED

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Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

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Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED

Test 25

Verdict: ACCEPTED

Test 26

Verdict: ACCEPTED

Test 27

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Test 28

Verdict: ACCEPTED

Test 29

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Test 30

Verdict: ACCEPTED

Test 31

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Test 32

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Test 33

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Test 34

Verdict: ACCEPTED

Test 35

Verdict: ACCEPTED

Test 36

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Test 37

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Test 38

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Test 39

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Test 40

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Test 41

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Test 42

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Test 43

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Test 44

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Test 45

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Test 46

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Test 47

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Test 48

Verdict: ACCEPTED

Test 49

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Test 50

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Test 51

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Test 52

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Test 53

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Test 54

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Test 55

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Test 56

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Test 57

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Test 58

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Test 59

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Test 60

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Test 61

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Test 80

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