圆排列问题

#include <iostream>
#include <fstream>
#include <queue>
#include <cmath>
using namespace std;

const int INF = 100000;
const int MAX = 50;
float r[MAX];  //圆的半径
int n; //圆的个数

class Node
{
public:
    int dep;      //当前层
    float len;    //圆排列长度
    float *x;       //当前圆排列圆心坐标
    float *r;       //当前圆排列

    Node(int d, float l)
    {
        x = new float[n+1];
        r = new float[n+1];
        dep = d;
        len = l;
    }

    //计算当前所选择圆的圆心
    float center(int t)
    {
        int j;
        float temp = 0.0;
        float valuex;
        for(j=1; j<t; j++)
        {
            valuex = x[j] + 2.0*sqrt(r[j]*r[t]);  //寻找当前层下最右边的圆心
            if(valuex > temp)
                temp = valuex;
        }   
        return temp;
    }

    //计算当前圆排列的长度
    float getLen(int t)
    {
        int i;
        float low = 0.0;  //圆位于原点右侧
        float high = 0.0;
        for(i=1; i<=t; i++)
        {
            if(x[i] - r[i] < low)  //寻找最左边的坐标，当圆位于原点左侧时才会更新
                low = x[i]-r[i];
            if(x[i] + r[i] > high)  //寻找最右边的坐标
                high = x[i]+r[i];
        } 
        return high - low;
    }

    //圆排列长度小的先出队列
    bool operator < (const Node &node) const
    {
        return len > node.len;
    }
};

float search()
{
    priority_queue<Node> q;
    Node enode(0, 0);
    copy(r, r+n+1, enode.r);
    for(int j=1; j<=n; j++)
        enode.x[j] = 0;
    float best = INF;
    do
    {
        if(enode.dep == n-1) //只有一个儿子结点
        {
            enode.x[n] = enode.center(n);
            enode.len = enode.getLen(n);
            if(enode.len < best)
            {
                best = enode.len; 
                break;
            }
        }
        else
        {
            for(int i=enode.dep+1; i<=n; i++)
            {
                Node now(enode.dep+1, enode.len);
                copy(enode.x, enode.x+n+1, now.x);      
                copy(enode.r, enode.r+n+1, now.r);
                now.r[now.dep] = enode.r[i];  
                now.r[i] = enode.r[now.dep];
                now.len = now.getLen(now.dep);
                now.x[now.dep] = now.center(now.dep); 
                if(now.len < best)
                    q.push(now);
            }
        }
        if(q.empty())
            break;
        else
        {
            enode = q.top();
            q.pop(); 
        }
    }while(enode.len < best);

    return best;
}

int main()
{
    ifstream fin("圆排列.txt");
    cout << "输入圆的个数：";
    fin >> n; cout << n;
    cout << "\n输入各圆的半径：\n";
    int i, j;
    for(i=1; i<=n; i++)
    {
        fin >> r[i];
        cout << r[i] << " ";
    }

    cout << "\n圆排列最小长度为：" << search();

    cout << endl;
    cout << endl;
    fin.close();
    return 0;
}