Follow up for N-Queens problem.

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

class Solution {public:void init(vector
     
       &temp, int n){    string strtemp(n,'.');    temp.insert(temp.end(),n,strtemp);    return;}bool checkij(vector
      
        &temp, int i, int j){    for (int ii=i-1,jleft=j-1;ii>=0&&jleft>=0;ii--,jleft--)    {        if(temp[ii][jleft]=='Q')return false;    }    for (int ii=i-1,jright=j+1;ii>=0&&jright
       
         &temp,int n, int index){    if(index==n)    {        res++;        return true;    }    for (int j=0;j
        
          temp;        init(temp,n);        for(int i=0;i