[LeetCode]N-Queens II

Follow up for N-Queens problem.

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

public class Solution {boolean[] column = null;boolean[] diag = null;boolean[] anti_diag = null;int[]C = null;int res = 0;    public int totalNQueens(int n) {        column = new boolean[n];        diag = new boolean[2*n];        anti_diag = new boolean[2*n];        C = new int[n];//Q在第i行的第几列        dfs(0,n);        return res;            }        private void dfs(int row,int n){    if(row==n){    res++;    return;    }    for(int j=0;j<n;j++){    if(!column[j]&&!anti_diag[row+j]&&!diag[n-row-1+j]){    C[row]=j;    }else{    continue;    }    column[j]=anti_diag[row+j]=diag[n-row-1+j]=true;    dfs(row+1,n);    column[j]=anti_diag[row+j]=diag[n-row-1+j]=false;    }    }}