main.py

from collections import deque
import sys


def solve(data: str) -> str:
    raw_lines = [line.rstrip() for line in data.splitlines() if line.strip()]
    if not raw_lines:
        return ""
    rows, cols = map(int, raw_lines[0].split())
    grid = raw_lines[1:1 + rows]
    start = (-1, -1)
    target = (-1, -1)
    for row in range(rows):
        for col in range(cols):
            if grid[row][col] == "S":
                start = (row, col)
            elif grid[row][col] == "T":
                target = (row, col)
    directions = ((1, 0, "D"), (0, -1, "L"), (0, 1, "R"), (-1, 0, "U"))
    queue = deque([start])
    visited = [[False] * cols for _ in range(rows)]
    parent = [[None] * cols for _ in range(rows)]
    visited[start[0]][start[1]] = True
    while queue:
        row, col = queue.popleft()
        if (row, col) == target:
            break
        for dr, dc, mark in directions:
            nxt_row = row + dr
            nxt_col = col + dc
            if not (0 <= nxt_row < rows and 0 <= nxt_col < cols):
                continue
            if visited[nxt_row][nxt_col] or grid[nxt_row][nxt_col] == "#":
                continue
            visited[nxt_row][nxt_col] = True
            parent[nxt_row][nxt_col] = (row, col, mark)
            queue.append((nxt_row, nxt_col))
    if not visited[target[0]][target[1]]:
        return "distance=-1\npath=NONE"
    path = []
    cur = target
    while cur != start:
        row, col = cur
        prev_row, prev_col, mark = parent[row][col]
        path.append(mark)
        cur = (prev_row, prev_col)
    path.reverse()
    return f"distance={len(path)}\npath={''.join(path)}"


if __name__ == "__main__":
    sys.stdout.write(solve(sys.stdin.read()).strip())
    sys.stdout.write("\n")