Luogu3855 [TJOI2008]Binary Land (BFS)

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#define R(a,b,c) for(register int  a = (b); a <= (c); ++ a)
#define nR(a,b,c) for(register int  a = (b); a >= (c); -- a)
#define Max(a,b) ((a) > (b) ? (a) : (b))
#define Min(a,b) ((a) < (b) ? (a) : (b))
#define Fill(a,b) memset(a, b, sizeof(a))
#define Swap(a,b) a^=b^=a^=b
#define ll long long
#define ON_DEBUG

#ifdef ON_DEBUG

#define D_e_Line printf("\n\n----------\n\n")
#define D_e(x)  cout << #x << " = " << x << endl
#define Pause() system("pause")

#else

#define D_e_Line ;

#endif

struct ios{
    template<typename ATP>ios& operator >> (ATP &x){
        x = 0; int f = 1; char c;
        for(c = getchar(); c < '0' || c > '9'; c = getchar()) if(c == '-')  f = -1;
        while(c >= '0' && c <= '9') x = x * 10 + (c ^ '0'), c = getchar();
        x*= f;
        return *this;
    }
}io;
using namespace std;

#define stone 2
#define spider 3
#define endPlace 9

const int N = 37;

int n, m;

struct MAP{
    int x_1, y_1, x_2, y_2, step;
}u, v;

#include<queue>

queue<MAP>q;

int mp[N][N];

int ans = 0x3f3f3f3f;

int walk_1[4][2]={{1,0},{0,1},{-1,0},{0,-1}};
int walk_2[4][2]={{1,0},{0,-1},{-1,0},{0,1}};

int vis[N][N][N][N];

inline void BFS(){
    vis[u.x_1][u.y_1][u.x_2][u.y_2] = true;
    q.push(u);
    while(!q.empty()){
        u = q.front();
        q.pop();
        
        if(mp[u.x_1][u.y_1] == endPlace && mp[u.x_2][u.y_2] == endPlace){
            ans = u.step;
            return; 
        }
        
        R(i,0,3){
            v.x_1 = u.x_1 + walk_1[i][0];
            v.y_1 = u.y_1 + walk_1[i][1];
            v.x_2 = u.x_2 + walk_2[i][0];
            v.y_2 = u.y_2 + walk_2[i][1];
            v.step = u.step + 1;
            if(v.x_1 < 1 || v.x_2 < 1 || v.y_1 < 1 || v.y_2 < 1 || v.x_1 > n || v.x_2 > n || v.y_1 > m || v.y_2 > m) continue;
            if(mp[v.x_1][v.y_1] == stone) v.x_1 = u.x_1, v.y_1 = u.y_1;
            if(mp[v.x_2][v.y_2] == stone) v.x_2 = u.x_2, v.y_2 = u.y_2;
            if(mp[v.x_1][v.y_1] == spider || mp[v.x_2][v.y_2] == spider) continue;
            if(vis[v.x_1][v.y_1][v.x_2][v.y_2]) continue;
            vis[v.x_1][v.y_1][v.x_2][v.y_2] = 1;
            q.push(v);
        }
    }

}

int st[2][2];
int main(){
    io >> n >> m;
    R(i,1,n){
        char str[57];
        scanf("%s", str + 1);
        R(j,1,m){
            switch(str[j]){
                case '#' :{
                    mp[i][j] = stone;
                    break;
                }
                case 'X' :{
                    mp[i][j] = spider;
                    break;
                }
                case 'T' :{
                    mp[i][j] = endPlace;
                    break;
                }
                case 'G' :{
                    mp[i][j] = 7;
                    st[0][0] = i, st[0][1] = j;
                    break;
                }
                case 'M' :{
                    mp[i][j] = 8;
                    st[1][0] = i, st[1][1] = j;
                    break;
                }
                case '.' :{
                    mp[i][j] = 1;
                    break;
                }
            }
        }
    }
    
    
    
    u = (MAP){st[0][0], st[0][1], st[1][0], st[1][1], 0};
    
    BFS();
    
    if(ans == 0x3f3f3f3f){
        printf("no");
    }
    else{
        printf("%d", ans);
    }
    
    return 0;
}