Follow up for N-Queens problem.

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

 

#include
          
           #include
           
            #include
            
             using namespace std;class Solution{public:    int res=0;    int totalNQueens(int n)    {        vector
             
               state(n,-1);        helper(n,0,state);        return res;    }    void helper(int n,int start,vector
              
                &state)    {        if(start==n)        {            res++;            return;        }        int i;        for(i=0; i
               

&state,int row,int col) { int i; for(i=0; i