Mkae the array palindrome

#include <bits/stdc++.h> 

int palindrome(vector<int> A)
{
	long long n = A.size();
	long long start = 0;
	long long end = n-1;
	long long count = 0;
	vector<long long> arr;
	for(auto x: A){
          arr.push_back( (long long)x );
        }
	while( start < end ){
		if( arr[start] == arr[end] ){
			start++;
			end--;
		} else if( arr[start] < arr[end] ) {
			arr[start+1] = arr[start] + arr[start+1];
			count++;
			start++;
			
		} else {
			
			arr[end-1] = arr[end] + arr[end-1];
			end--;
			count++;
		}
	}
	return count;
}