class Solution { vector<int> col, dg, udg; int n; public: /** * * @param n int整型 the n * @return int整型 */ int Nqueen(int _n) { // write code here n = _n; col = vector<int>(n); dg = udg = vector<int>(2 * n); return dfs(0); } int dfs(int x) { if (x == n) return 1; else { int res = 0;...