noip模拟赛 c

分析：一道比较难的爆搜题.首先要把9个块的信息存下来，记录每个块上下左右位置的颜色,然后记录每一排每一列能否操作，之后就是bfs了。在bfs的时候用一个数记录状态，第i位表示原来的第i个块现在在哪个位置,我们可以通过这个状态来解码得到信息，也可以来判重，只是数组开不下，需要用一个map。然后就是如何判断是否连通.首先把所有块还原成一张图，然后我们可以数每个颜色连通的数量，看看是不是等于36就可以了，这里用dfs来判断.

学习了一种比较强的记录状态的方式：记录相对位置，既可以判重，也可以还原图.

#include <cstdio>
#include <map>
#include <queue>
#include <cstring>
#include <iostream>
#include <algorithm>

using namespace std;

int canx[], cany[], zhuangtai[];
int can[], vis[][], a[][];
map <long long, int> flag;

struct node
{
    int col[];
}e[];

struct node2
{
    long long stu;
    int dist;
};

long long hashh(int a, int b, int c, int d, int e, int f, int g, int h, int i)
{
    return (((((((a *  + b) *  + c) *  + d) *  + e) *  + f) *  + g) *  + h) *  + i;
}

int dfs(int col, int x, int y, int last)
{
    //printf("%d %d %d %d\n", col, x, y, last);
    int ret = ;
    if (vis[x][y] || (a[x][y] != col && a[x][y] != ) || (a[x][y] ==  && last == ))
        return ret;
    vis[x][y] = ;
    if (col == a[x][y])
        ret++;
    if (x > )
        ret += dfs(col, x - , y, a[x][y]);
    if (x < )
        ret += dfs(col, x + , y, a[x][y]);
    if (y > )
        ret += dfs(col, x, y - , a[x][y]);
    if (y < )
        ret += dfs(col, x, y + , a[x][y]);
    return ret;
}

bool check(long long stu)
{
    //printf("%lld\n", stu);
    int res = ;
    memset(can, , sizeof(can));
    memset(a, , sizeof(a));
    for (int i = ; i >= ; i--)
        for (int j = ; j >= ; j--)
        {
        int x = stu % ;
        a[i * ][j *  + ] = e[x].col[];
        a[i *  + ][j *  + ] = e[x].col[];
        a[i *  + ][j * ] = e[x].col[];
        a[i *  + ][j *  + ] = e[x].col[];
        stu /= ;
        }
    for (int i = ; i <= ; i++)
    {
        for (int j = ; j <= ; j++)
            printf("%d ", a[i][j]);
        printf("\n");
    }
    printf("\n");
    for (int i = ; i < ; i++)
        for (int j = ; j < ; j++)
            for (int k = ; k <= ; k++)
                if (!can[k] && a[i][j] == k)
                {
                    memset(vis, , sizeof(vis));
                    res += dfs(k, i, j, );
                    can[k] = ;
                }
    if (res == )
        return true;
    return false;
}

void bfs()
{
    queue <node2> q;
    node2 temp;
    temp.stu = ;
    temp.dist = ;
    q.push(temp);
    flag[] = ;
    while (!q.empty())
    {
        node2 u = q.front();
        q.pop();
        long long stu = u.stu;
        int dist = u.dist;
        //printf("%lld %d\n", stu, dist);
        if (check(stu))
        {
            printf("%d\n", dist);
            return;
        }
        //printf("flag\n");
        for (int i = ; i >= ; i--)
        {
            zhuangtai[i] = stu % ;
            stu /= ;
        }
        if (!canx[])
        {
            long long nstu = hashh(zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[]);
            //printf("%lld\n", nstu);
            if (!flag[nstu])
            {
                node2 temp;
                temp.stu = nstu;
                temp.dist = dist + ;
                q.push(temp);
            }
            nstu = hashh(zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[]);
            //printf("%lld\n", nstu);
            if (!flag[nstu])
            {
                node2 temp;
                temp.stu = nstu;
                temp.dist = dist + ;
                q.push(temp);
            }
        }
        if (!canx[])
        {
            long long nstu = hashh(zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[]);
            if (!flag[nstu])
            {
                node2 temp;
                temp.stu = nstu;
                temp.dist = dist + ;
                q.push(temp);
            }
            nstu = hashh(zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[]);
            if (!flag[nstu])
            {
                node2 temp;
                temp.stu = nstu;
                temp.dist = dist + ;
                q.push(temp);
            }
        }

        if (!canx[])
        {
            long long nstu = hashh(zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[]);
            if (!flag[nstu])
            {
                node2 temp;
                temp.stu = nstu;
                temp.dist = dist + ;
                q.push(temp);
            }
            nstu = hashh(zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[]);
            if (!flag[nstu])
            {
                node2 temp;
                temp.stu = nstu;
                temp.dist = dist + ;
                q.push(temp);
            }
        }

        if (!cany[])
        {
            long long nstu = hashh(zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[]);
            if (!flag[nstu])
            {
                node2 temp;
                temp.stu = nstu;
                temp.dist = dist + ;
                q.push(temp);
            }
            nstu = hashh(zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[]);
            if (!flag[nstu])
            {
                node2 temp;
                temp.stu = nstu;
                temp.dist = dist + ;
                q.push(temp);
            }
        }

        if (!cany[])
        {
            long long nstu = hashh(zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[]);
            if (!flag[nstu])
            {
                node2 temp;
                temp.stu = nstu;
                temp.dist = dist + ;
                q.push(temp);
            }
            nstu = hashh(zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[]);
            if (!flag[nstu])
            {
                node2 temp;
                temp.stu = nstu;
                temp.dist = dist + ;
                q.push(temp);
            }
        }

        if (!cany[])
        {
            long long nstu = hashh(zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[]);
            if (!flag[nstu])
            {
                node2 temp;
                temp.stu = nstu;
                temp.dist = dist + ;
                q.push(temp);
            }
            nstu = hashh(zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[], zhuangtai[]);
            if (!flag[nstu])
            {
                node2 temp;
                temp.stu = nstu;
                temp.dist = dist + ;
                q.push(temp);
            }
        }
    }
}

void init()
{
    for (int i = ; i < ; i++)
    {
        int t;
        for (int j = ; j < ; j++)
        {
            char ch;
            cin >> ch;
            if (ch == 'R')
                e[i].col[j] = ;
            if (ch == 'G')
                e[i].col[j] = ;
            if (ch == 'B')
                e[i].col[j] = ;
            if (ch == 'O')
                e[i].col[j] = ;
        }
        cin >> t;
        if (t == )
        {
            canx[i / ] = ;
            cany[i % ] = ;
        }
    }
}

int main()
{
    init();
    bfs();

    return ;
}