Submission #1150400

#	Time	Username	Problem	Language	Result	Execution time	Memory
1150400		xnscdev	Mecho (IOI09_mecho)	C++20	84 / 100	135 ms	6228 KiB

mecho

// https://oj.uz/problem/view/IOI09_mecho

#ifndef DEBUG
#pragma GCC optimize("Ofast,unroll-loops")
#endif

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/trie_policy.hpp>

#if defined(DEBUG) && defined(DEBUG_UTIL)
#include "dsa_util.h"
#endif

// clang-format off
using namespace std;
using namespace __gnu_pbds;
using uint = unsigned int;
using ll = long long;
using ull = unsigned long long;

constexpr int INF = 0x3f3f3f3f;
constexpr ll INFL = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-9;
constexpr int dx[8] = {1, -1, 0, 0, 1, 1, -1, -1};
constexpr int dy[8] = {0, 0, 1, -1, 1, -1, 1, -1};
constexpr int drev[8] = {1, 0, 3, 2, 7, 6, 5, 4};
constexpr char dn_nsew[4] = {'S', 'N', 'E', 'W'};
constexpr char dn_udrl[4] = {'D', 'U', 'R', 'L'};
unordered_map<char, int> dm_nsew = {{'S', 0}, {'N', 1}, {'E', 2}, {'W', 3}};
unordered_map<char, int> dm_udrl = {{'D', 0}, {'U', 1}, {'R', 2}, {'L', 3}};
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

#if __cplusplus < 202002L
template <typename T> int popcount(T x); template <> int popcount(uint x) { return __builtin_popcount(x); } template <> int popcount(ull x) { return __builtin_popcountll(x); }
template <typename T> int countl_zero(T x); template <> int countl_zero(uint x) { return __builtin_clz(x); } template <> int countl_zero(ull x) { return __builtin_clzll(x); }
template <typename T> int countr_zero(T x); template <> int countr_zero(uint x) { return __builtin_ctz(x); } template <> int countr_zero(ull x) { return __builtin_ctzll(x); }
template <typename T> int bit_width(T x) { return numeric_limits<T>::digits - countl_zero(x); }
#endif

template <typename T> int sgn(T x) { return (T(0) < x) - (x < T(0)); }
template <typename T> T randint(T l, T r) { return uniform_int_distribution<T>(l, r)(rng); }
template <typename T> T randf(T l, T r) { return uniform_real_distribution<T>(l, r)(rng); }
template <typename T> int log2if(T x) { return bit_width(x) - 1; }
template <typename T> int log2ic(T x) { return bit_width(x - 1); }
bool inside(int x, int y, int n, int m) { return x >= 0 && x < n && y >= 0 && y < m; }
ll sqdist(const pair<int, int> &p, const pair<int, int> &q) { ll x = p.first - q.first, y = p.second - q.second; return x * x + y * y; }

#if __cplusplus >= 201703L
template <typename T> using min_priority_queue = priority_queue<T, vector<T>, greater<>>;
template <typename T, typename Comp = less<>> using ordered_set = tree<T, null_type, Comp, rb_tree_tag, tree_order_statistics_node_update>;
using pref_trie = trie<string, null_type, trie_string_access_traits<>, pat_trie_tag, trie_prefix_search_node_update>;

template <typename, typename = void> struct is_iterable : false_type {};
template <typename T> struct is_iterable<T, void_t<decltype(declval<T>().begin()), decltype(declval<T>().end())>> : true_type {};
template <> struct is_iterable<string> : false_type {};
template <typename T> constexpr bool is_iterable_v = is_iterable<T>::value;
template <typename T, typename V = enable_if_t<is_iterable_v<T>, typename T::value_type>> ostream &operator<<(ostream &os, const T &t) { for (const V &v : t) os << v << ' '; return os; }
template <typename T, typename U> ostream &operator<<(ostream &os, const pair<T, U> &p) { return os << '(' << p.first << ' ' << p.second << ')'; }
void dbg_header_(const char *f, int l, const char *e) { cout << "\033[35m(" << f << ':' << l << ") \033[1m" << e << ":\033[0m "; }
template <typename T, typename = enable_if_t<!is_iterable_v<T>>> void dbg_(const T &t, const char *f, int l, const char *e) { dbg_header_(f, l, e); cout << "\033[33;1m" << t << "\033[0m" << endl; }
template <typename T, typename V = enable_if_t<is_iterable_v<T> && !is_iterable_v<typename T::value_type>, typename T::value_type>, typename = void> void dbg_(const T &t, const char *f, int l, const char *e) { dbg_header_(f, l, e); cout << "\033[33;1m"; for (const V &v : t) cout << v << ' '; cout << "\033[0m" << endl; }
template <typename T, typename = enable_if_t<is_iterable_v<T> && is_iterable_v<typename T::value_type>, typename T::value_type>, typename = void, typename = void> void dbg_(const T &t, const char *f, int l, const char *e) { dbg_header_(f, l, e); cout << '\n'; for (int i = 0; i < t.size(); i++) cout << "\033[36m" << i << ":\033[33;1m " << t[i] << "\033[0m" << endl; }
#ifdef DEBUG
#define dbg(t) dbg_((t), __func__, __LINE__, #t)
#else
#define dbg(t)
#endif
#endif
// clang-format on

void solve()
{
#ifdef DEBUG
    cout << "\033[31;1m======================================================================\033[0m" << endl;
#endif
    int n, s;
    cin >> n >> s;
    vector<string> grid(n);
    vector dist_bees(n, vector<int>(n, -1));
    queue<pair<int, int>> q;
    pair<int, int> start, end;
    for (int i = 0; i < n; i++)
    {
        grid[i].resize(n);
        for (int j = 0; j < n; j++)
        {
            cin >> grid[i][j];
            switch (grid[i][j])
            {
            case 'M':
                start = {i, j};
                break;
            case 'D':
                end = {i, j};
                break;
            case 'H':
                q.emplace(i, j);
                dist_bees[i][j] = 0;
                break;
            default:
                break;
            }
        }
    }
    while (!q.empty())
    {
        auto [x, y] = q.front();
        q.pop();
        for (int i = 0; i < 4; i++)
        {
            int nx = x + dx[i], ny = y + dy[i];
            if (!inside(nx, ny, n, n) || dist_bees[nx][ny] != -1 || grid[nx][ny] == 'T' || grid[nx][ny] == 'D')
                continue;
            dist_bees[nx][ny] = dist_bees[x][y] + 1;
            q.emplace(nx, ny);
        }
    }
    auto ok = [&](int t)
    {
        vector dist_mecho(n, vector<int>(n, -1));
        dist_mecho[start.first][start.second] = 0;
        q.push(start);
        while (!q.empty())
        {
            auto [x, y] = q.front();
            q.pop();
            for (int i = 0; i < 4; i++)
            {
                int nx = x + dx[i], ny = y + dy[i];
                if (!inside(nx, ny, n, n) || dist_mecho[nx][ny] != -1 || grid[nx][ny] == 'T' || grid[nx][ny] == 'D' || (dist_mecho[x][y] + 1) / s >= dist_bees[nx][ny] - t)
                    continue;
                dist_mecho[nx][ny] = dist_mecho[x][y] + 1;
                q.emplace(nx, ny);
            }
        }
        for (int i = 0; i < 4; i++)
        {
            int x = end.first + dx[i], y = end.second + dy[i];
            if (inside(x, y, n, n) && dist_mecho[x][y] != -1)
                return true;
        }
        return false;
    };
    int l = 0, r = n * n;
    int ans = -1;
    while (l <= r)
    {
        int mid = l + (r - l) / 2;
        if (ok(mid))
        {
            ans = mid;
            l = mid + 1;
        }
        else
        {
            r = mid - 1;
        }
    }
    cout << ans << endl;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int t = 1;
    // cin >> t;
    while (t--)
        solve();
}

• Subtask 1: 84 / 100