Error main: malloc.c:2401: sysmalloc: Assertion Doing a simple C++ fibonacci assignment

I am working on this assignment and i trying to figure this out. When i input any other numbers between 1 to 10 except 6. The fibonacci_fast(n) outputs an error main: malloc.c:2401: sysmalloc: Assertion. However, when i use an array to replace the vector or just uncomment the std::cout. It will work fine. Can anyone enlighten me what’s the error that i have made.

#include <iostream>
#include <cassert>
#include <vector>
#include <algorithm>



int fibonacci_naive(int n) {
        if (n <= 1)
        return n;

    return fibonacci_naive(n - 1) + fibonacci_naive(n - 2);
    
}

int fibonacci_fast(int n) {

    std::vector<int> numbers{0,n};
    numbers[0] =0;
    numbers[1] =1;
    int ans=0;
    if (n <= 1)
    {
        return n;
    }
    
        //std::cout<<std::endl;
        //int numbers[n];

        for(int i=2;i<=n;i++)
        {
            numbers[i] = numbers[i-1] + numbers[i-2];
            
        }

        ans = numbers[n];

        return ans;
    

    
}

void test_solution() {
    assert(fibonacci_fast(3) == 2);
    assert(fibonacci_fast(10) == 55);
    for (int n = 0; n < 20; ++n)
        assert(fibonacci_fast(n) == fibonacci_naive(n));
}

int main() {
    int n = 0;
    std::cin >> n;

    //std::cout << fibonacci_naive(n) << '\n';
    //test_solution();
    std::cout << fibonacci_fast(n) << std::endl;
    return 0;
}

>Solution :

std::vector<int> numbers{0,n}; creates a vector of size 2, not of size n. You probably want to use std::vector<int> numbers(n, 0).