TEMPBAL problem , I used if-else , got correct with first two test cases then wrong ans , help

help
,
1

My issue

What I am doing wrong here for first 2 test lines it works correct then for others it failed , could anyone please let me know where I got wrong ?

My code

#include <bits/stdc++.h>
using namespace std;

bool allZero(vector<int>& arr) {
    for(int x : arr) if(x != 0) return false;
    return true;
}

int helper(int N, int second, vector<int>&arr) {
     while(!allZero(arr)){
         for(int i=0; i<N-1; i++) {
        if(arr[i] > arr[i+1]) {
            arr[i]--;
            arr[i+1]++;
            second++;
        }
        else if(arr[i] < arr[i+1]) {
            arr[i]++;
            arr[i+1]--;
            second++;
        }
     }
   }
    return second;
}

int main() {
    int t;
    cin >> t;
    while(t--) {
        int N;
        cin >> N;
        int second = 0;
        vector<int> arr(N);
        for(int i=0; i<N; i++) {
            cin >> arr[i];
        }
        cout << helper(N, second, arr) << endl;
    }
    return 0;
}

Problem Link: Temperature Balance Practice Coding Problem