用栈求解汉诺塔问题

#include <iostream>
#include <stack>
#include <string>
#include <climits>
using namespace std;
/*
*  用递归解法解汉诺塔问题
*
*/
/*
int process(int num, string left, string mid, string right,
            string from, string to)
            {
                if(num == 1)
                {
                    if(from == mid || to == mid)
                    {
                        cout << "move 1 from " << from << " to " << to << endl;
                        return 1;
                    }

                    else
                    {
                        cout << "move 1 from" << from << " to " << mid << "\n"
                        << "move 1 from " << mid << " to " << to << endl;
                        return 2;
                    }
                }

                if(from == mid || to == mid)
                {
                    string str = (from == left || to == left) ? right : left;
                    int part1 = process(num - 1, left, mid, right, from, str);
                    int part2 = 1;
                    cout << "move " << num << " from " << from << " to " << to << endl;
                    int part3 = process(num - 1 , left, mid, right, str, to);
                    return part1 + part2 + part3;
                }
                else {
                    int part1 = process(num - 1, left, mid, right, from, to);
                    int part2 = 1;
                    cout << "move " << num << " from " << from << " to " << mid << endl;
                    int part3 = process(num - 1, left, mid, right, to, from);
                    int part4 = 1;
                    cout << "move " << num << " from " << mid << " to " <<to << endl;
                    int part5 = process(num - 1, left, mid, right, from, to);
                    return part1 + part2 + part3 + part4 + part5;
                }
            }

int hanoiProlem1(int num, string left, string mid, string right)
{
    if(num < 1)
        return 0;
    return process(num, left, mid, right, left, right);
}
*/

/*
*  用非递归解法解汉诺塔问题
*
*/
enum Action {No, LToM, MToL, MToR, RToM};
int fStackAction(Action& record, Action preNoAct, Action nowAct, stack<int>& LS,
                 stack<int>& MS, string from, string to)
                 {
                     if(record != preNoAct && LS.top() < MS.top())
                     {
                         int val = LS.top();
                         LS.pop();
                         MS.push(val);
                         cout << "move " << val << " from " << from << " to " << to << endl;
                         record = nowAct;
                         return 1;
                     }
                     return 0;
                 }



int hanoiProblem2(int num, string left, string mid, string right)
{
    stack<int> Ls;
    stack<int> Ms;
    stack<int> Rs;

    Ls.push(INT_MAX);
    Ms.push(INT_MAX);
    Rs.push(INT_MAX);

    for(int i = num ; i > 0; --i)
    Ls.push(i);

    Action record = No;
    int step = 0;
    while(Rs.size() != num + 1)
    {
        step += fStackAction(record, MToL, LToM, Ls, Ms, left, mid);
        step += fStackAction(record, LToM, MToL, Ms, Ls, mid, left);
        step += fStackAction(record, MToR, RToM, Rs, Ms, mid, right);
        step += fStackAction(record, RToM, MToR, Ms, Rs, right, mid);
    }
    return step;
}
int main()
{
    cout << hanoiProblem2(3, "left", "mid", "right");
}