1032 挖掘机技术哪家强 请看看哪里有问题？

```#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n;
    cin >> n;
    int arr[n] = {0};
    int num = 0, grade = 0, max = arr[0], maxnum = 0;
    for(int i = 0; i < n; i++)
    {
        cin >> num >> grade;
        arr[num] += grade;
        if(arr[num] > max)
        {
            int tmp = arr[num];
            arr[num] = max;
            max = tmp;
            maxnum = num;
        }
    }
    cout << maxnum << " " << max;
} 

int arr[n]能编译通过啊？