三个测试点错 求解

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

struct Node {
int row;
int col;
int time;
};

int main() {
int R, C;
cin >> R >> C;

vector<vector<char>> maze(R, vector<char>(C));
vector<vector<bool>> visited(R, vector<bool>(C, false));
queue<Node> q;
Node den;

for (int i = 0; i < R; i++) {
    for (int j = 0; j < C; j++) {
        cin >> maze[i][j];
        if (maze[i][j] == 'S') {
            q.push({i, j, 0});
            visited[i][j] = true;
        } else if (maze[i][j] == 'D') {
            den.row = i;
            den.col = j;
        }
    }
}

while (!q.empty()) {
    Node current = q.front();
    q.pop();

    if (current.row == den.row && current.col == den.col) {
        cout << current.time << endl;
        return 0;
    }

    int dr[] = {1, -1, 0, 0};
    int dc[] = {0, 0, 1, -1};

    for (int i = 0; i < 4; i++) {
        int newRow = current.row + dr[i];
        int newCol = current.col + dc[i];

        if (newRow >= 0 && newRow < R && newCol >= 0 && newCol < C && !visited[newRow][newCol] && maze[newRow][newCol] != 'X' && maze[newRow][newCol] != '*') {
            q.push({newRow, newCol, current.time + 1});
            visited[newRow][newCol] = true;
        }
    }
}

cout << "KAKTUS" << endl;

return 0;

}