原题目：

解题思路：动态规划

代码：

ll R[50][11][2048];void solve() {ll i, j,k,x,y,z,p,q,u,v;N = 40, NN = 1024;//N = 20;double a, b, c,d;for (i = 0; i <= 9; i++) {R[1][i][1 << i] = 1;}for (i = 2; i <= N; i++) {for (j = 0; j <= 9 ; j++) {for (k = 0; k < 1024; k++) {if (j - 1 >= 0) {R[i][j][k | (1 << j)] += R[i - 1][j - 1][k];}if (j + 1 <= 9) {R[i][j][k | (1 << j)] += R[i - 1][j + 1][k];}}if (j != 0) {ans1 = ans1 + R[i][j][1023];}}}printf("%lld\n",ans1);
}