Leetcode no. 52

52. 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 count=0;    public int totalNQueens(int n){        solveNQueens(0, 0, n, new int[n]);        return count;    }    private void solveNQueens(int row, int col, int n, int[] column){        if (row == n)            count++;        else{            for (int i = col; i < n; i++) {                column[row]= i;                boolean f= true;                for (int r = row-1, lc= i-1, rc= i+1; r>=0 ; r--,lc--,rc++ ) {                    if (column[r]== i || column[r]==lc || column[r]==rc) f= false;                }                if (f) solveNQueens(row+1, 0, n, column);            }        }    }}