} //回溯，判断另一种符号情况 for(j=2; j<=t; ++j) {

counter -= p[j][t-j+1]; }

counter -= i; } } }

int main() {

cout << "请输入第一行符号个数n："; cin >> n; counter = 0; sum = 0;

half = n*(n+1)/2; int i=0;

if( half%2 == 0 )

{//总数须为偶数，若为奇数则无解 half /= 2;

p = new uchar *[n+1];

for(i=0; i<=n; ++i)

{

p[i] = new uchar[n+1];

memset(p[i], 0, sizeof(uchar)*(n+1)); }

Backtrace(1); for(i=0; i<=n; ++i) {

delete[] p[i]; }

delete[] p; }

cout << "\n总共 " << sum << " 个"<< endl; return 0; }