四阶幻方的穷举求解.

速度太慢了,有时间研究构造四阶幻方的构造法…..

#include "iostream"#include "algorithm"#include "queue"#include "vector"#include "list"using namespace std;bool isused[17] = { false };int board[17];queue<int>x;#define M 34void print(int count){    cout << "case :" << count << endl;    for (size_t beg = 1; beg != 17; beg+=4)    {        cout << board[beg] << " \t" << board[beg + 1] << "\t "            << board[beg + 2] << " \t" << board[beg + 3]<<endl;    }    cout<< "====================================" << endl;}bool check(){    if (board[13] + board[14] + board[15] + board[16] != M)        return false;    return board[1] + board[6] + board[11] + board[16] == M&&         board[4] + board[7] + board[10] + board[13] == M ? true : false;}void func(int n){    static int index = 0;    if (n == 17)    {        if (check())//符合要求            print(++index);        return;    }    if(n<=12)    {        int count = x.size();        while (--count!=-1)//使用队列里面现有的元素        {            auto m = x.front();            x.pop();            board[n] = m;            isused[m] = true;            do            {                if (!(n % 4) && board[n] + board[n - 1] + board[n - 2] + board[n - 3] != M)                    break;                if (n ==11 && board[n] + board[n - 1] + board[n - 4] + board[n - 5] != M)                    break;              func(n + 1);            } while (0);            isused[m] = false;            x.push(m);        }    }    else    {        int m = M - board[n - 4] - board[n - 8] - board[n - 12];        if (m > 0 && m < 17 && !isused[m])        {            board[n] = m;            isused[m] = true;            func(n + 1);            isused[m] = false;        }    }}int main(){    for (size_t i = 1; i != 17; ++i)        x.push(i);    func(1);    return 0;}