C++ 代码

最简单直白（菜）的写法。

#include <bits/stdc++.h>
using namespace std;
int ans = 0;

int main() {
    ios :: sync_with_stdio(false);
    cin.tie(0);

    string temp = "";
    string str = "";
    getline(cin,temp);    str+=temp;
    getline(cin,temp);    str+=temp;

    int ay = 0,by = 0,ky = 0,kb=0;
    for(int i = 0 ; i < str.size();i++){
        if (str[i] == 'A')ay = i;
        if (str[i] == 'B')by = i;
        if (str[i] == ' ')ky = i;
    }

    queue<string> que,next;
    queue<int> prq;
    map<string, int> mp;
    mp[str]++;
    prq.push(ky);
    que.push(str);

    while (1){
        if (que.empty())
        {
            ans++;
            swap(que, next);
            //cout<<'*'<<que.size()<<'*'<<ans<<endl;
        }
        str = que.front();
        kb = prq.front();

        if (kb<3){
            swap(str[kb], str[kb+3]);
            if (str[ay] == 'B' && str[by] == 'A')
                break;
            if (!mp[str])
            {
                kb+=3;
                prq.push(kb);
                next.push(str);
                mp[str]++;
                kb-=3;
            }
            swap(str[kb], str[kb+3]);
        }
        if(kb>2){
            swap(str[kb], str[kb-3]);
            if (str[ay] == 'B' && str[by] == 'A')
                break;
            if (!mp[str])
            {
                kb-=3;
                prq.push(kb);
                next.push(str);
                mp[str]++;
                kb+=3;
            }
            swap(str[kb], str[kb-3]);
        }
        if(kb == 0 || kb == 1 || kb == 3 || kb == 4){
                swap(str[kb], str[kb+1]);
                if (str[ay] == 'B' && str[by] == 'A')
                    break;
                if (!mp[str])
                {
                    kb+=1;
                    prq.push(kb);
                    next.push(str);
                    mp[str]++;
                    kb-=1;
                }
                swap(str[kb], str[kb+1]);
        }
        if(kb == 2 || kb == 1 || kb == 5 || kb == 4){
                swap(str[kb], str[kb-1]);
                if (str[ay] == 'B' && str[by] == 'A')
                    break;
                if (!mp[str])
                {
                    kb-=1;
                    prq.push(kb);
                    next.push(str);
                    mp[str]++;
                    kb+=1;
                }
                swap(str[kb], str[kb-1]);
        }
        que.pop();
        prq.pop();
    }
    cout<<ans+1;
    return 0;
}