7-17 汉诺塔的非递归实现 (25 分)

#include<stdio.h>
#include<stdlib.h>

int main()
{
    int i;
    int n;
    int topa = -1;
    int topb = -1;
    int topc = -1;
    int temp;
    int to = 1;  //用to表示当前最小值所在的柱子，1为a，2为b
    int count ;
    scanf("%d",&n);
    int a[n];
    int b[n];
    int c[n];

    count = 0;  //如果n是偶数，那运行完成后C柱上有n个元素，奇数的话B柱上有n个元素

    for( i=n; i>0; i--)
    {
        a[++topa] = i;   //初始化低层数值大

    }
    while( 1 )
    {
        if( n%2==0)
        {
            //这里主要处理n为偶数第一步放在b上
            if( to==1)
            {
                //当前最小值在a上,往前移一步
                temp = a[topa--];
                b[++topb] = temp;
                to = 2;
                printf("a -> b\n");
                if( a[topa]<c[topc] || c[topc]==0)
                {
                    //如果a的最小值<c的最小值或者c为空,则将a的最小值移到c
                    temp = a[topa--];
                    c[++topc] = temp;
                    printf("a -> c\n");
                    count++;
                    if(count==n)
                    {
                        break;
                    }
                }
                else
                {
                    //否则将c的最小值移动到a
                    temp = c[topc--];
                    a[++topa] = temp;
                    printf("c -> a\n");
                    count--;
                }

            }
            else if( to==2)
            {
                temp = b[topb--];
                c[++topc] = temp;
                to = 3;
                printf("b -> c\n");
                count++;
                if(count==n)
                {
                    break;
                }
                if( a[topa]<b[topc] || b[topb]==0)
                {
                    temp = a[topa--];
                    b[++topb] = temp;
                    printf("a -> b\n");
                }
                else
                {
                    temp = b[topb--];
                    a[++topa] = temp;
                    printf("b -> a\n");
                }

            }
            else if( to==3)
            {
                temp = c[topc--];
                a[++topa] = temp;
                to = 1;
                printf("c -> a\n");
                count--;
                if( b[topa]<c[topc] || c[topc]==0)
                {
                    temp = b[topb--];
                    c[++topc] = temp;
                    printf("b -> c\n");
                    count++;
                    if(count==n)
                    {
                        break;
                    }
                }
                else
                {
                    temp = c[topc--];
                    b[++topb] = temp;
                    printf("c -> b\n");
                    count--;
                }

            }
        }

        else
        {
            //这里主要处理n为奇数第一步放在c上
            if( to==1)
            {
                temp = a[topa--];
                b[++topb] = temp;
                to = 2;
                printf("a -> c\n");
                count++;
                if(count==n)
                {
                    break;
                }
                if( a[topa]<c[topc] || c[topc]==0)
                {
                    temp = a[topa--];
                    c[++topc] = temp;
                    printf("a -> b\n");

                }
                else
                {
                    temp = c[topc--];
                    a[++topa] = temp;
                    printf("b -> a\n");
                }

            }
            else if( to==2)
            {
                temp = b[topb--];
                c[++topc] = temp;
                to = 3;
                printf("c -> b\n");
                count--;
                if( a[topa]<b[topc] || b[topb]==0)
                {
                    temp = a[topa--];
                    b[++topb] = temp;
                    printf("a -> c\n");
                    count++;
                    if(count==n)
                    {
                        break;
                    }
                }
                else
                {
                    temp = b[topb--];
                    a[++topa] = temp;
                    printf("c -> a\n");
                    count--;
                }

            }
            else if( to==3)
            {
                temp = c[topc--];
                a[++topa] = temp;
                to = 1;
                printf("b -> a\n");
                if( b[topa]<c[topc] || c[topc]==0)
                {
                    temp = b[topb--];
                    c[++topc] = temp;
                    printf("c -> b\n");
                    count--;
                }
                else
                {
                    temp = c[topc--];
                    b[++topb] = temp;
                    printf("b -> c\n");
                    count++;
                    if(count==n)
                    {
                        break;
                    }
                }

            }

        }
    }
    return 0;

}