LeetCode Solutions : N-Queens II

Follow up for N-Queens problem.

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

Java Solutions( Refer to blog  http://blog.csdn.net/mbh_1991/article/details/23869459 and  http://blog.csdn.net/u011095253/article/details/9158473   ):

public class Solution {
	int count;
    public int totalNQueens(int n) {
        count=0;
		int[] location=new int[n];
		dfs(location,0,n);
		return count;
    }
	private void dfs(int[] location,int cur,int n){
		if(cur==n)
			count++;
		else{
			for(int i=0;i<n;i++){
				location[cur]=i;
				if(isValid(location,cur))
					dfs(location,cur+1,n);
			}
		}
	}
	private boolean isValid(int[] location,int cur){
		for(int i=0;i<cur;i++){
			if(location[i]==location[cur]||Math.abs(location[i]-location[cur])==cur-i)
				return false;
		}
		return true;
	}
}