Establish equality

input/code.cpp: In function 'int main()':
input/code.cpp:31:26: warning: comparison of integer expressions of different signedness: 'size_t' {aka 'long unsigned int'} and 'int64_t' {aka 'long int'} [-Wsign-compare]
   31 |     for (size_t i = 0; i < n; i++)
      |                        ~~^~~

#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <stdint.h>
using namespace std;

bool isValidSolution(const vector<int64_t>& bottles, int64_t target)
{
    int64_t deficit, surplus;
    deficit = surplus = 0;
    for (size_t i = 0; i < bottles.size(); i++)
    {
        if (bottles[i] < target)
        {
            deficit += target - bottles[i];
        }
        else
        {
            surplus += bottles[i] - target;
        }
    }
    return surplus >= 2 * deficit;
}

int main()
{
    int64_t n;
    cin >> n;
    vector<int64_t> bottles(n);
    for (size_t i = 0; i < n; i++)
    {
        cin >> bottles[i];
    }

    int64_t bestSolution = 0;
    int64_t a = 0, b = 1000000000;
    while (a < b)
    {
        int64_t k = a + (b - a) / 2;
        if (isValidSolution(bottles, k))
        {
            bestSolution = k;
            a = k + 1;
        }
        else
        {
            b = k - 1;
        }
    }
    cout << bestSolution << endl;

}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: ACCEPTED

Test 8

Verdict: WRONG ANSWER

Test 9

Verdict: ACCEPTED

Test 10

Verdict: WRONG ANSWER

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: WRONG ANSWER

Test 15

Verdict: WRONG ANSWER

Test 16

Verdict: WRONG ANSWER

Test 17

Verdict: WRONG ANSWER

Test 18

Verdict: WRONG ANSWER

Test 19

Verdict: WRONG ANSWER

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: WRONG ANSWER

Test 24

Verdict: WRONG ANSWER

Test 25

Verdict: ACCEPTED

Test 26

Verdict: ACCEPTED

Test 27

Verdict: ACCEPTED

Test 28

Verdict: WRONG ANSWER

Test 29

Verdict: ACCEPTED

Test 30

Verdict: ACCEPTED

Test 31

Verdict: WRONG ANSWER

Test 32

Verdict: ACCEPTED

Test 33

Verdict: ACCEPTED

Test 34

Verdict: ACCEPTED

Test 35

Verdict: ACCEPTED

Test 36

Verdict: WRONG ANSWER

Test 37

Verdict: ACCEPTED

Test 38

Verdict: WRONG ANSWER

Test 39

Verdict: ACCEPTED

Test 40

Verdict: WRONG ANSWER

Test 41

Verdict: WRONG ANSWER

Test 42

Verdict: ACCEPTED

Test 43

Verdict: WRONG ANSWER

Test 44

Verdict: WRONG ANSWER

Test 45

Verdict: WRONG ANSWER

Test 46

Verdict: WRONG ANSWER

Test 47

Verdict: WRONG ANSWER

Test 48

Verdict: WRONG ANSWER

Test 49

Verdict: WRONG ANSWER

Test 50

Verdict: ACCEPTED

Test 51

Verdict: ACCEPTED

Test 52

Verdict: WRONG ANSWER

Test 53

Verdict: WRONG ANSWER

Test 54

Verdict: ACCEPTED

Test 55

Verdict: ACCEPTED