178 lines
3.4 KiB
C++
178 lines
3.4 KiB
C++
#include <bits/stdc++.h> // {{{
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#include <version>
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#ifdef __cpp_lib_ranges_enumerate
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#include <ranges>
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namespace rv = std::views;
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namespace rs = std::ranges;
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#endif
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// https://codeforces.com/blog/entry/96344
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#pragma GCC optimize("O2,unroll-loops")
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#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
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using namespace std;
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using i32 = int32_t;
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using u32 = uint32_t;
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using i64 = int64_t;
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using u64 = uint64_t;
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using f64 = double;
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using f128 = long double;
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#if __cplusplus >= 202002L
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template <typename T>
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constexpr T MIN = std::numeric_limits<T>::min();
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template <typename T>
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constexpr T MAX = std::numeric_limits<T>::max();
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template <typename T>
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[[nodiscard]] static T sc(auto&& x) {
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return static_cast<T>(x);
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}
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template <typename T>
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[[nodiscard]] static T sz(auto&& x) {
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return static_cast<T>(x.size());
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}
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#endif
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static void NO() {
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std::cout << "NO\n";
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}
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static void YES() {
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std::cout << "YES\n";
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}
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template <typename T>
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using vec = std::vector<T>;
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#define all(x) (x).begin(), (x).end()
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#define rall(x) (x).rbegin(), (x).rend()
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#define ff first
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#define ss second
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#ifdef LOCAL
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#define db(...) std::print(__VA_ARGS__)
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#define dbln(...) std::println(__VA_ARGS__)
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#else
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#define db(...)
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#define dbln(...)
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#endif
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// }}}
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static map<char, pair<i32, i32>> dirs{
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{'R', {0, 1}}, {'L', {0, -1}}, {'D', {1, 0}}, {'U', {-1, 0}}};
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void solve() {
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u32 n, m;
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cin >> n >> m;
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vec<string> graph(n);
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for (auto& e : graph)
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cin >> e;
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queue<pair<i32, i32>> mq, aq;
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u32 sr, sc;
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for (u32 r = 0; r < n; ++r) {
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for (u32 c = 0; c < m; ++c) {
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if (graph[r][c] == 'M') {
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mq.emplace(r, c);
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graph[r][c] = '#';
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} else if (graph[r][c] == 'A') {
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sr = r, sc = c;
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aq.emplace(r, c);
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}
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}
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}
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auto valid = [&n, &m](i32 r, i32 c) -> bool {
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return min(r, c) >= 0 && r < n && c < m;
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};
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vec<string> trace(n, string(m, ' '));
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auto print_trace = [&](i32 r, i32 c) -> void {
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vec<char> path;
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while (r != sr || c != sc) {
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path.push_back(trace[r][c]);
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auto dir = dirs.at(trace[r][c]);
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r -= dir.first;
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c -= dir.second;
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}
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reverse(all(path));
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cout << "YES\n" << path.size() << '\n';
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for (auto e : path)
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cout << e;
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};
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while (!aq.empty()) {
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u32 mcount = mq.size();
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for (u32 i = 0; i < mcount; ++i) {
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auto [r, c] = mq.front();
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mq.pop();
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for (auto& [_, dir] : dirs) {
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auto nr = r + dir.first, nc = c + dir.second;
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if (!valid(nr, nc) || graph[nr][nc] == '#') {
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continue;
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}
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graph[nr][nc] = '#';
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mq.emplace(nr, nc);
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}
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}
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u32 acount = aq.size();
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for (u32 i = 0; i < acount; ++i) {
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auto [r, c] = aq.front();
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aq.pop();
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if (r == 0 || r == n - 1 || c == 0 || c == m - 1) {
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print_trace(r, c);
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return;
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}
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for (auto& [letter, dir] : dirs) {
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auto nr = r + dir.first, nc = c + dir.second;
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if (!valid(nr, nc) || trace[nr][nc] != ' ' || graph[nr][nc] == '#') {
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continue;
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}
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trace[nr][nc] = letter;
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aq.emplace(nr, nc);
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}
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}
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}
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NO();
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}
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int main() { // {{{
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std::cin.exceptions(std::cin.failbit);
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#ifdef LOCAL
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std::cerr.rdbuf(std::cout.rdbuf());
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std::cout.setf(std::ios::unitbuf);
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std::cerr.setf(std::ios::unitbuf);
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#else
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std::cin.tie(nullptr)->sync_with_stdio(false);
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#endif
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u32 tc = 1;
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// std::cin >> tc;
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for (u32 t = 0; t < tc; ++t) {
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solve();
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}
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return 0;
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}
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// }}}
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