HDU 1043 Eight

HDU_1043

    老大之前让我研究了一下构造不限定步数的八数码的解，而自己苦于没有可行的套路迟迟没有用代码实现出来，今天又交流了一下忽然顿悟到如果把空位每次都固定在一个位置然后再枚举需要动的数字就可以比较容易地用代码实现出来了。其实后来才发现，也只是想起来容易，敲起来一样很复杂，搞了几个小时才完工-_-||。由于没有去写基本操作的小函数导致代码又臭又长，还出了几个错误导致调了几个小时，回头再和老大一块精简下代码吧。

#include<stdio.h>
#include<string.h>
char q[1010], b[5];
int p, g[10];
void init()
{
    int i;
    if(b[0] == 'x')
        g[0] = 0;
    else
        g[0] = b[0] - '0';
    for(i = 1; i < 9; i ++)
    {
        scanf("%s", b);
        if(b[0] == 'x')
            g[i] = 0;
        else
            g[i] = b[0] - '0';
    }
}
void solve()
{
    int i, j, k;
    char u = 'u', d = 'd', l = 'l', r = 'r';
    p = 0;
    //(1) blank ready
    if(!g[0])
    {
        q[p ++] = d; q[p ++] = r;
        g[0] = g[3], g[3] = g[4], g[4] = 0;
    }
    else if(!g[1])
    {
        q[p ++] = d;
        g[1] = g[4], g[4] = 0;
    }
    else if(!g[2])
    {
        q[p ++] = d; q[p ++] = l;
        g[2] = g[5], g[5] = g[4], g[4] = 0;
    }
    else if(!g[3])
    {
        q[p ++] = r;
        g[3] = g[4], g[4] = 0;
    }
    else if(!g[5])
    {
        q[p ++] = l;
        g[5] = g[4], g[4] = 0;
    }
    else if(!g[6])
    {
        q[p ++] = r; q[p ++] = u;
        g[6] = g[7], g[7] = g[4], g[4] = 0;
    }
    else if(!g[7])
    {
        q[p ++] = u;
        g[7] = g[4], g[4] = 0;
    }
    else if(!g[8])
    {
        q[p ++] = l; q[p ++] = u;
        g[8] = g[7], g[7] = g[4], g[4] = 0;
    }
    //(2) 3 ready
    if(g[1] == 3)
    {
        q[p ++] = l; q[p ++] = u; q[p ++] = r; q[p ++] = d;
        g[4] = g[0]; g[0] = g[1]; g[1] = g[3]; g[3] = g[4]; g[4] = g[0];
    }
    else if(g[2] == 3)
    {
        q[p ++] = u; q[p ++] = r; q[p ++] = d; q[p ++] = l;
        q[p ++] = l; q[p ++] = u; q[p ++] = r; q[p ++] = d;
        g[4] = g[0]; g[0] = g[2]; g[2] = g[5]; g[5] = g[1]; g[1] = g[3]; g[3] = g[4]; g[4] = 0;
    }
    else if(g[3] == 3)
    {
        q[p ++] = u; q[p ++] = l; q[p ++] = d; q[p ++] = r;
        g[4] = g[0]; g[0] = g[3]; g[3] = g[1]; g[1] = g[4]; g[4] = 0;
    }
    else if(g[5] == 3)
    {
        q[p ++] = r; q[p ++] = u; q[p ++] = l; q[p ++] = d;
        q[p ++] = l; q[p ++] = u; q[p ++] = r; q[p ++] = d;
        g[4] = g[0]; g[0] = g[5]; g[5] = g[2]; g[2] = g[1]; g[1] = g[3]; g[3] = g[4]; g[4] = 0;
    }
    else if(g[6] == 3)
    {
        q[p ++] = l; q[p ++] = d; q[p ++] = r; q[p ++] = u;
        q[p ++] = u; q[p ++] = l; q[p ++] = d; q[p ++] = r;
        g[4] = g[0]; g[0] = g[6]; g[6] = g[7]; g[7] = g[3]; g[3] = g[1]; g[1] = g[4]; g[4] = 0;
    }
    else if(g[7] == 3)
    {
        q[p ++] = d; q[p ++] = l; q[p ++] = u; q[p ++] = r;
        q[p ++] = u; q[p ++] = l; q[p ++] = d; q[p ++] = r;
        g[4] = g[0]; g[0] = g[7]; g[7] = g[6]; g[6] = g[3]; g[3] = g[1]; g[1] = g[4]; g[4] = 0;
    }
    else if(g[8] == 3)
    {
        q[p ++] = d; q[p ++] = r; q[p ++] = u; q[p ++] = l;
        q[p ++] = d; q[p ++] = l; q[p ++] = u; q[p ++] = r;
        q[p ++] = u; q[p ++] = l; q[p ++] = d; q[p ++] = r;
        g[4] = g[0]; g[0] = g[8]; g[8] = g[5]; g[5] = g[7]; g[7] = g[6]; g[6] = g[3]; g[3] = g[1]; g[1] = g[4]; g[4] = 0;
    }
    //(3) 2 ready
    if(g[1] == 2)
    {
        q[p ++] = u; q[p ++] = r; q[p ++] = d; q[p ++] = l;
        q[p ++] = r; q[p ++] = d; q[p ++] = l; q[p ++] = u;
        q[p ++] = d; q[p ++] = l; q[p ++] = u; q[p ++] = r;
        g[4] = g[1]; g[1] = g[2]; g[2] = g[5]; g[5] = g[8]; g[8] = g[7]; g[7] = g[6]; g[6] = g[3]; g[3] = g[4]; g[4] = 0;
    }
    else if(g[2] == 2)
    {
        q[p ++] = r; q[p ++] = u; q[p ++] = l; q[p ++] = d;
        q[p ++] = r; q[p ++] = d; q[p ++] = l; q[p ++] = u;
        q[p ++] = d; q[p ++] = l; q[p ++] = u; q[p ++] = r;
        g[4] = g[1]; g[1] = g[5]; g[5] = g[8]; g[8] = g[7]; g[7] = g[6]; g[6] = g[3]; g[3] = g[2]; g[2] = g[4]; g[4] = 0;
    }
    else if(g[5] == 2)
    {
        q[p ++] = r; q[p ++] = d; q[p ++] = l; q[p ++] = u;
        q[p ++] = d; q[p ++] = l; q[p ++] = u; q[p ++] = r;
        g[4] = g[3]; g[3] = g[5]; g[5] = g[8]; g[8] = g[7]; g[7] = g[6]; g[6] = g[4]; g[4] = 0;
    }
    else if(g[6] == 2)
    {
        q[p ++] = l; q[p ++] = d; q[p ++] = r; q[p ++] = u;
        g[4] = g[3]; g[3] = g[6]; g[6] = g[7]; g[7] = g[4]; g[4] = 0;
    }
    else if(g[7] == 2)
    {
        q[p ++] = d; q[p ++] = l; q[p ++] = u; q[p ++] = r;
        g[4] = g[3]; g[3] = g[7]; g[7] = g[6]; g[6] = g[4]; g[4] = 0;
    }
    else if(g[8] == 2)
    {
        q[p ++] = d; q[p ++] = r; q[p ++] = u; q[p ++] = l;
        q[p ++] = d; q[p ++] = l; q[p ++] = u; q[p ++] = r;
        g[4] = g[3]; g[3] = g[8]; g[8] = g[5]; g[5] = g[7]; g[7] = g[6]; g[6] = g[4]; g[4] = 0;
    }
    //(4) 1 ready
    if(g[6] == 1)
    {
        q[p ++] = d;
        g[4] = g[7]; g[7] = 0;
        for(i = 0; i < 5; i ++)
        {
            q[p ++] = l; q[p ++] = u; q[p ++] = u; q[p ++] = r; q[p ++] = r; q[p ++] = d; q[p ++] = d; q[p ++] = l;
        }
        g[7] = g[0]; g[0] = g[6]; g[6] = g[5]; g[5] = g[1]; g[1] = g[3]; g[3] = g[8]; g[8] = g[2]; g[2] = g[7]; g[7] = 0;
    }
    else
    {
        // 1 in the 5th place
        if(g[1] == 1)
        {
            q[p ++] = u; q[p ++] = r; q[p ++] = d; q[p ++] = l;
            g[4] = g[1]; g[1] = g[2]; g[2] = g[5]; g[5] = g[4]; g[4] = 0;
        }
        else if(g[2] == 1)
        {
            q[p ++] = r; q[p ++] = u; q[p ++] = l; q[p ++] = d;
            g[4] = g[1]; g[1] = g[5]; g[5] = g[2]; g[2] = g[4]; g[4] = 0;
        }
        else if(g[7] == 1)
        {
            q[p ++] = d; q[p ++] = r; q[p ++] = u; q[p ++] = l;
            g[4] = g[5]; g[5] = g[7]; g[7] = g[8]; g[8] = g[4]; g[4] = 0;
        }
        else if(g[8] == 1)
        {
            q[p ++] = r; q[p ++] = d; q[p ++] = l; q[p ++] = u;
            g[4] = g[5]; g[5] = g[8]; g[8] = g[7]; g[7] = g[4]; g[4] = 0;
        }
        // other operations
        q[p ++] = r;
        g[4] = g[5]; g[5] = 0;
        for(i = 0; i < 3; i ++)
        {
            q[p ++] = l; q[p ++] = l; q[p ++] = u; q[p ++] = r; q[p ++] = r; q[p ++] = d;
        }
        g[5] = g[0]; g[0] = g[4]; g[4] = g[1]; g[1] = g[3]; g[3] = g[2]; g[2] = g[5]; g[5] = 0;
        q[p ++] = l; q[p ++] = d;
        g[5] = g[4]; g[4] = g[7]; g[7] = 0;
    }
    //(5) 4 ready
    if(g[3] == 4)
    {
        q[p ++] = u; q[p ++] = l; q[p ++] = d; q[p ++] = r;
        q[p ++] = r; q[p ++] = u; q[p ++] = l; q[p ++] = d;
        g[7] = g[3]; g[3] = g[6]; g[6] = g[4]; g[4] = g[8]; g[8] = g[5]; g[5] = g[7]; g[7] = 0;
    }
    else if(g[4] == 4)
    {
        q[p ++] = r; q[p ++] = u; q[p ++] = l; q[p ++] = d;
        g[7] = g[4]; g[4] = g[8]; g[8] = g[5]; g[5] = g[7]; g[7] = 0;
    }
    else if(g[6] == 4)
    {
        q[p ++] = l; q[p ++] = u; q[p ++] = r; q[p ++] = d;
        q[p ++] = r; q[p ++] = u; q[p ++] = l; q[p ++] = d;
        g[7] = g[3]; g[3] = g[4]; g[4] = g[8]; g[8] = g[5]; g[5] = g[6]; g[6] = g[7]; g[7] = 0;
    }
    else if(g[8] == 4)
    {
        q[p ++] = u; q[p ++] = r; q[p ++] = d; q[p ++] = l;
        g[7] = g[4]; g[4] = g[5]; g[5] = g[8]; g[8] = g[7]; g[7] = 0;
    }
    //(6) 5 ready
    if(g[8] != 5)
    {
        if(g[3] == 5)
        {
            q[p ++] = l; q[p ++] = u; q[p ++] = r; q[p ++] = d;
            g[7] = g[3]; g[3] = g[4]; g[4] = g[6]; g[6] = g[7]; g[7] = 0;
        }
        else if(g[4] == 5)
        {
            q[p ++] = u; q[p ++] = l; q[p ++] = d; q[p ++] = r;
            g[7] = g[3]; g[3] = g[6]; g[6] = g[4]; g[4] = g[7]; g[7] = 0;
        }
        q[p ++] = r; q[p ++] = u; q[p ++] = l; q[p ++] = d;
        g[7] = g[4]; g[4] = g[8]; g[8] = g[5]; g[5] = g[7]; g[7] = 0;
        q[p ++] = r;
        g[7] = g[8]; g[8] = 0;
        q[p ++] = l; q[p ++] = l; q[p ++] = u; q[p ++] = r; q[p ++] = r; q[p ++] = d; q[p ++] = l;
        g[8] = g[6]; g[6] = g[3]; g[3] = g[4]; g[4] = g[5]; g[5] = g[7]; g[7] = 0;
    }
    //(7) 6 ready
    if(g[3] == 6)
    {
        q[p ++] = u; q[p ++] = l; q[p ++] = d; q[p ++] = r;
        g[7] = g[3]; g[3] = g[6]; g[6] = g[4]; g[4] = g[7]; g[7] = 0;
    }
    else if(g[6] == 6)
    {
        q[p ++] = l; q[p ++] = u; q[p ++] = r; q[p ++] = d;
        g[7] = g[3]; g[3] = g[4]; g[4] = g[6]; g[6] = g[7]; g[7] = 0;
    }
    q[p ++] = u;
    g[7] = g[4]; g[4] = 0;
    q[p ++] = r; q[p ++] = d; q[p ++] = l; q[p ++] = l; q[p ++] = u; q[p ++] = r; q[p ++] = r; q[p ++] = d;
    g[4] = g[8]; g[8] = g[3]; g[3] = g[5]; g[5] = g[7]; g[7] = g[6]; g[6] = g[8]; g[8] = 0;
    //(8) check
    if(g[6] == 8)
        printf("unsolvable\n");
    else
    {
        q[p] = '\0';
        printf("%s\n", q);
    }
}
int main()
{
    while(scanf("%s", b) == 1)
    {
        init();
        solve();
    }
    return 0;
}