第一题,dfs/dp dfs: def dfs(pb, i, j, n, res): if j == n-1: if i == 1: res[0] += 1 return for ne in get_neigh(i, j, n): if pb[ne[0]][ne[1]]: pb[ne[0]][ne[1]] == False dfs(pb, ne[0], ne[1], n, res) pb[ne[0]][ne[1]] ...