Revise paste Untitled

#include <iostream>
#include <queue>
#include <vector>
using namespace std;

int n, m;
char mat[101][101];
int bfs(pair<int, int> S, pair<int, int> E) {
    int si = S.first, sj = S.second;
    int ei = E.first, ej = E.second;
    queue<int> q;
    q.push(si);
    q.push(sj);
    q.push(0);
    
    vector<vector<bool>> visited(n, vector<bool>(m, false));
    visited[si][sj] = true;
    while(!q.empty()) {
        int ci = q.front();
        q.pop();
        int cj = q.front();
        q.pop();
        int dist = q.front();
        q.pop();
        
        if(ci == ei and cj == ej) {
            return dist;
        }
        if(ci + 1 < n and mat[ci + 1][cj] != '#' and !visited[ci + 1][cj]) {
            q.push(ci + 1);
            q.push(cj);
            q.push(dist + 1);
            visited[ci + 1][cj] = true;
        }
        if(ci - 1 >= 0 and mat[ci - 1][cj] != '#' and !visited[ci - 1][cj]) {
            q.push(ci - 1);
            q.push(cj);
            q.push(dist + 1);
            visited[ci - 1][cj] = true;
        }
        if(cj + 1 < m and mat[ci][cj + 1] != '#' and !visited[ci][cj + 1]) {
            q.push(ci);
            q.push(cj + 1);
            q.push(dist + 1);
            visited[ci][cj + 1] = true;
        }
        if(cj - 1 >= 0 and mat[ci][cj - 1] != '#' and !visited[ci][cj - 1]) {
            q.push(ci);
            q.push(cj - 1);
            q.push(dist + 1);
            visited[ci][cj - 1] = true;
        }
        
    }
    return 1e8;
}
int main() {
    cin >> n >> m;
    
    pair<int, int> S, E;
    vector<pair<int, int>> drinks;
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++) {
            cin >> mat[i][j];
            
            if(mat[i][j] == 'S') {
                S = make_pair(i, j);
            }
            if(mat[i][j] == 'B') {
                E = make_pair(i, j);
            }
            if(mat[i][j] == 'D') {
                drinks.push_back(make_pair(i, j));
            }
        }
    }
    
    int res = 2e9;
    
    if(drinks.size() == 1) {
        res = bfs(S, drinks[0]) + bfs(drinks[0], E);
    }
    else if(drinks.size() == 2) {
        res = bfs(S, drinks[0]) + bfs(drinks[0], drinks[1]) + bfs(drinks[1], E);
        
        res = min(res, bfs(S, drinks[1]) + bfs(drinks[1], drinks[0]) + bfs(drinks[0], E));
        
    }
    else {
        res = bfs(S, drinks[0]) + bfs(drinks[0], drinks[1]) + bfs(drinks[1], drinks[2]) + bfs(drinks[2], E);
        res = min(res, bfs(S, drinks[0]) + bfs(drinks[0], drinks[2]) + bfs(drinks[2], drinks[1]) + bfs(drinks[1], E));
        res = min(res, bfs(S, drinks[1]) + bfs(drinks[1], drinks[0]) + bfs(drinks[0], drinks[2]) + bfs(drinks[2], E));
        res = min(res, bfs(S, drinks[1]) + bfs(drinks[1], drinks[2]) + bfs(drinks[2], drinks[0]) + bfs(drinks[0], E));
        res = min(res, bfs(S, drinks[2]) + bfs(drinks[2], drinks[0]) + bfs(drinks[0], drinks[1]) + bfs(drinks[1], E));
        res = min(res, bfs(S, drinks[2]) + bfs(drinks[2], drinks[1]) + bfs(drinks[1], drinks[0]) + bfs(drinks[0], E));
        
    }
    if(res > 1e8) {
        res = -1;
    }
    cout << res << endl;
    return 0;
}