main.cpp

#include <algorithm>
#include <deque>
#include <iostream>
#include <string>
#include <tuple>
#include <vector>

using namespace std;

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

    int rows, cols;
    if (!(cin >> rows >> cols)) {
        return 0;
    }
    vector<string> grid(rows);
    pair<int, int> start = {-1, -1};
    pair<int, int> target = {-1, -1};
    for (int row = 0; row < rows; ++row) {
        cin >> grid[row];
        for (int col = 0; col < cols; ++col) {
            if (grid[row][col] == 'S') {
                start = {row, col};
            } else if (grid[row][col] == 'T') {
                target = {row, col};
            }
        }
    }
    const int dr[4] = {1, 0, 0, -1};
    const int dc[4] = {0, -1, 1, 0};
    const char mark[4] = {'D', 'L', 'R', 'U'};
    deque<pair<int, int>> queue;
    vector<vector<int>> visited(rows, vector<int>(cols, 0));
    vector<vector<tuple<int, int, char>>> parent(rows, vector<tuple<int, int, char>>(cols, {-1, -1, '?'}));
    queue.push_back(start);
    visited[start.first][start.second] = 1;
    while (!queue.empty()) {
        auto [row, col] = queue.front();
        queue.pop_front();
        if (make_pair(row, col) == target) {
            break;
        }
        for (int dir = 0; dir < 4; ++dir) {
            int nxt_row = row + dr[dir];
            int nxt_col = col + dc[dir];
            if (nxt_row < 0 || nxt_row >= rows || nxt_col < 0 || nxt_col >= cols) {
                continue;
            }
            if (visited[nxt_row][nxt_col] || grid[nxt_row][nxt_col] == '#') {
                continue;
            }
            visited[nxt_row][nxt_col] = 1;
            parent[nxt_row][nxt_col] = {row, col, mark[dir]};
            queue.push_back({nxt_row, nxt_col});
        }
    }
    if (!visited[target.first][target.second]) {
        cout << "distance=-1\n";
        cout << "path=NONE\n";
        return 0;
    }
    string path;
    pair<int, int> cur = target;
    while (cur != start) {
        auto [prev_row, prev_col, step] = parent[cur.first][cur.second];
        path.push_back(step);
        cur = {prev_row, prev_col};
    }
    reverse(path.begin(), path.end());
    cout << "distance=" << path.size() << "\n";
    cout << "path=" << path << "\n";
    return 0;
}