N-Queens II

Follow up for N-Queens problem.

Now, instead outputting board configurations, return the total number of distinct solutions.

public class Solution {
    int result = 0;
    public int totalNQueens(int n) {
        // Start typing your Java solution below
        // DO NOT write main() function
        result = 0;
        solve(new int[n], 0);
        return result;
    }
    public void solve(int[] arr, int pos){
        int size = arr.length;
        if(pos == size){
            result ++;
            return;
        }
        for(int i = 0; i < size; i ++)
            if(isValid(arr, pos, i)){
                arr[pos] = i;
                solve(arr, pos + 1);    
            } 
    }
    public boolean isValid(int[] arr, int pos, int check){
        for(int i = 0; i < pos; i ++)
            if(check == arr[i] || Math.abs(pos - i) == Math.abs(check - arr[i])) return false;
        return true;
    }
}