筆試題：求二叉樹中和值爲sum的所有路徑

#include <iostream>
#include <stack>
using namespace std;
struct Node
{
    Node *left;
    Node *right;
    int data;
    Node(int d = int()) :data(d), left(NULL), right(NULL){}
};

class DataTree
{
public:
    DataTree():root(NULL){}
    void Create_Tree(int VLR[],int LVR[],int n)
    {
        Create_Tree(root,VLR,LVR,n);//由數組的前序跟中序構造二叉樹。
    }
    void Printf()
    {
        Printf(root);
    }
    void Printf(Node *t)
    {
        if (t != NULL)
        {
            cout << t->data << " ";
            Printf(t->left);
            Printf(t->right);
        }
    }
    void GetSum(int sum)//求取和值爲sum的所有路徑.
    {
        //這裏如果要保存，要用到棧。
        stack<int> st;
        GetSum(st, root, sum);
    }
private:
    void GetSum(stack<int> &st, Node *t, int sum)
    {
        if (t == NULL)
        {
            if (sum == 0)
            {
                stack<int> temp = st;
                while (temp.empty() == false)
                {
                    cout << temp.top() << endl;
                    temp.pop();
                }
            }
            return ;
        }
        else
        {
            sum -= t->data;
            st.push(t->data);
            GetSum(st,t->left,sum);

            if (t->right!=NULL)
            GetSum(st,t->right,sum);
            st.pop();
        }
    }
    void Create_Tree(Node *&t,int VLR[],int LVR[],int n)
    {
        if (n == 0)return;
        int i = 0;
        while (VLR[0] != LVR[i])i++;
        t = new Node(VLR[0]);
        Create_Tree(t->left,VLR+1,LVR,i);
        Create_Tree(t->right,VLR+i+1,LVR+i+1,n-i-1);
    }
private:
    Node *root;
};
int main()
{
    int VLR[] = {1,2,3,4,5,6,7};
    int LVR[] = {3,2,4,1,6,5,7};
    DataTree dt;
    dt.Create_Tree(VLR,LVR,sizeof(LVR)/sizeof(int));
    dt.GetSum(13);
    return 0;
}