import java.util.*; public class Solution { /** * * @param n int整型 the n * @return int整型 */ int sum = 0; // int vnum = 0; public int Nqueen (int n) { // write code here int[][] visit = new int[n][n]; Stack<int []> stack = new Stack(); dfs(n, stack, 0, 0, 0, 0); return sum; } public void dfs(in...