Gas tank

input/code.cpp: In function 'int main()':
input/code.cpp:70:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'long long unsigned int' [-Wsign-compare]
   70 |         if (volumeAB > maxVolume) {
      |             ~~~~~~~~~^~~~~~~~~~~

#include <bits/stdc++.h>

using namespace std;

#define debug(...) Debug(#__VA_ARGS__, __VA_ARGS__);
template <typename... Args>
void Debug(const char* names, Args&&... args) {
   std::cerr << names << " = ";
   ((std::cerr << args << ", "), ...) << "\b\b " << std::endl;
}
#define ll long long
#define ull unsigned long long
#define vi vector<int>

// Returns floor of square root of x
ull floorSqrt(ull x)
{
    // Base cases
    if (x == 0 || x == 1)
        return x;

    // Starting from 1, try all numbers until
    // i*i is greater than or equal to x.
    ull i = 1, result = 1;
    while (result <= x) {
        i++;
        result = i * i;
    }
    return i - 1;
}


ull volume(ull A, ull B) {
    return A * A * B + B * B * A;
}

int binary_search_B(ull A, ull N, ull upbound) {
    int l = 1, r = upbound;
    int bestB = 0;

    while (l <= r) {
        ull mid = (l + r) / 2;
        ull vol = volume(A, mid);

        if (vol <= N) {
            bestB = mid;  // Update bestB to the current mid
            l = mid + 1;  // Try a larger B to maximize volume
        } else {
            r = mid - 1;  // Try a smaller B if volume exceeded N
        }
    }
    
    return bestB;
}

int main() {
    ull N;
    cin >> N;

    ull maxVolume = 0;
    ull bestA = 1, bestB = 1;

    ull upper_bound = floorSqrt(N);


    for (ull A = 1; A <= upper_bound; ++A) {
        ull B = binary_search_B(A, N, upper_bound);
        long long volumeAB = volume(A, B);

        if (volumeAB > maxVolume) {
            maxVolume = volumeAB;
            bestA = A;
            bestB = B;
        }
    }

    cout << bestA << " " << bestB << endl;
    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

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Test 6

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Test 7

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Test 8

Verdict: ACCEPTED

Test 9

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Test 10

Verdict: ACCEPTED

Test 11

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Test 12

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Test 13

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Test 14

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Test 15

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Test 16

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Test 17

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Test 18

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Test 19

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Test 20

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Test 21

Verdict: ACCEPTED

Test 22

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Test 23

Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED

Test 25

Verdict: ACCEPTED

Test 26

Verdict: ACCEPTED

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Verdict: ACCEPTED

Test 28

Verdict: ACCEPTED

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Test 30

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Test 32

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Verdict: ACCEPTED

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Test 40

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Test 43

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Test 44

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Test 45

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Test 48

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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 62

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Test 70

Verdict: ACCEPTED

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Verdict: ACCEPTED

Test 72

Verdict: ACCEPTED

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Verdict: ACCEPTED

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Verdict: ACCEPTED

Test 75

Verdict: ACCEPTED

Test 76

Verdict: ACCEPTED

Test 77

Verdict: ACCEPTED

Test 78

Verdict: ACCEPTED

Test 79

Verdict: ACCEPTED

Test 80

Verdict: ACCEPTED