Submission #988357

#	Time	Username	Problem	Language	Result	Execution time	Memory
988357		steveonalex	Mecho (IOI09_mecho)	C++17	67 / 100	198 ms	8016 KiB

mecho

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
 
#define MASK(i) (1ULL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()
 
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
 
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ll mask){return __builtin_popcountll(mask);}
int ctz(ull mask){return __builtin_ctzll(mask);}
int logOf(ull mask){return 63 - __builtin_clzll(mask);}
 
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}
 
template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b) {a = b; return true;}
        return false;
    }
 
template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b) {a = b; return true;}
        return false;
    }
 
template <class T>
    void printArr(T container, string separator = " ", string finish = "\n", ostream &out = cout){
        for(auto item: container) out << item << separator;
        out << finish;
    }
 
template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }

int dx[] = {0, 0, 1, -1};
int dy[] = {1, -1, 0, 0};

const int N = 900;
const int INF = 1e6 + 69;
int n, s;
bitset<N> grid[N];
int dis1[N][N], dis2[N][N];

int main(void){
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    cin >> n >> s;
    vector<string> field(n);
    for(int i = 0; i<n; ++i) cin >> field[i];

    for(int i = 0; i<=n+1; ++i) grid[i][0] = grid[0][i] = grid[i][n+1] = grid[n+1][i] = 1;
    for(int i = 0; i<n; ++i) for(int j = 0 ;j<n; ++j) if (field[i][j] == 'T' || field[i][j] == 'D'){
        grid[i+1][j+1] = 1;
    }

    for(int i = 0; i<=n+1; ++i) for(int j = 0; j<=n+1; ++j) dis1[i][j] = INF;

    deque<pair<int, int>> q;
    for(int i = 0; i<n; ++i) for(int j = 0; j<n; ++j) if (field[i][j] == 'H') {
        q.push_back({i + 1, j+1});
        dis1[i+1][j+1] = 0;
    }

    while(q.size()){
        pair<int, int> u = q.front(); q.pop_front();

        for(int dir = 0; dir < 4; ++dir){
            pair<int, int> v = {u.first + dx[dir], u.second + dy[dir]};
            if (!grid[v.first][v.second] && minimize(dis1[v.first][v.second], dis1[u.first][u.second] + 1)){
                q.push_back(v);
            }
        }
    }

    pair<int, int> S, E;
    for(int i = 0; i<n; ++i) for(int j = 0; j<n; ++j){
        if (field[i][j] == 'D') E = {i+1, j+1};
        if (field[i][j] == 'M') S = {i+1, j+1};
    }

    grid[E.first][E.second] = 0;

    ll l = -1, r = 2 * n * n;
    minimize(r, dis1[S.first][S.second] * s - 1);
    while(l < r){
        ll mid = (l + r + 1) >> 1;
        for(int i = 0; i<=n+1; ++i) for(int j = 0; j<=n+1; ++j) dis2[i][j] = INF;

        dis2[S.first][S.second] = mid;

        deque<pair<int, int>> q; q.push_back(S);
        while(q.size()){
            pair<int, int> u = q.front(); q.pop_front();

            int cur = dis2[u.first][u.second];

            for(int dir = 0; dir < 4; ++dir){
                pair<int, int> v = {u.first + dx[dir], u.second + dy[dir]};
                if (!grid[v.first][v.second] && dis1[v.first][v.second] > (cur + 1) / s && minimize(dis2[v.first][v.second], cur + 1)){
                    q.push_back(v);
                }
            }
        }
        if (dis2[E.first][E.second] == INF) r = mid - 1;
        else l = mid;
    }

    if (l >= 0) l /= s;

    cout << l << "\n";

    return 0;
}

• Subtask 1: 67 / 100