제출 #953342

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
953342		snowman	Mecho (IOI09_mecho)	C++17	100 / 100	272 ms	6460 KiB

mecho

#include <bits/stdc++.h>
using namespace std;
//Soltan Cristian
#define ll long long
#define all(x) x.begin(), x.end()
#define mod 1000000007
#define pb push_back
#define st first
#define nd second
#define sz(x) (ll)x.size()
#define rall(x) x.rbegin(), x.rend()

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

const int mxa = 2 * 1e5 + 2;
// string __fname = "maxflow";  
// ifstream in(__fname + ".in"); 
// ofstream out (__fname + ".out"); 
// #define cin in 
// #define cout out
int n, s;
vector<vector<char>> mapa;

bool validB(int x, int y){
    if(x >= 0 && x < n && y >= 0 && y < n && mapa[x][y] != 'T' && mapa[x][y] != 'D'){
        return true;
    }
    return false;
}

bool valid(int x, int y){
    if(x >= 0 && x < n && y >= 0 && y < n && mapa[x][y] != 'T'){
        return true;
    }
    return false;
}


void solve(){
    cin >> n >> s;
    mapa = vector<vector<char>>(n, vector<char>(n));
    vector<pair<int,int>> stup;
    pair<int, int> start, finish;
    for(int i = 0; i < n; i++){
        for(int j = 0; j < n; j++){
            char x;
            cin >> x;
            if(x == 'H') stup.pb({i, j});
            if(x == 'M') start = {i, j};
            if(x == 'D') finish = {i, j};
            mapa[i][j] = x;
        }
    }
    vector<vector<int>> bees(n, vector<int>(n, INT_MAX));
    queue<pair<int, int>> qB;
    for(int i = 0; i < sz(stup); i++){
        bees[stup[i].st][stup[i].nd] = 0;
        qB.push({stup[i].st, stup[i].nd});
    }
    // cout << "a\n";
    while(!qB.empty()){
        pair<int, int> u = qB.front();
        qB.pop();
        for(int i = 0; i < 4; i++){
            if(!validB(u.st + dx[i], u.nd + dy[i])) continue;
            if(bees[u.st][u.nd] + s < bees[u.st + dx[i]][u.nd + dy[i]]){
                qB.push({u.st + dx[i], u.nd + dy[i]});
                bees[u.st + dx[i]][u.nd + dy[i]] = bees[u.st][u.nd] + s;
            }
        }
    }
    if(bees[start.st][start.nd] == INT_MAX){
        cout << -1 << '\n';
        return;
    }
    // for(auto i : bees){
    //     for(auto j : i){
    //         if(j == INT_MAX){
    //             cout << -1 << ' ';
    //         }
    //         else cout << j << ' ';
    //     }
    //     cout << '\n';
    // }
    int l = 0, r = 1e9;
    // cout << r<< '\n';
    int ans = -1;
    while(l <= r){
        int mid = (l + r) / 2;
        vector<vector<int>> h(n, vector<int>(n, INT_MAX));
        h[start.st][start.nd] = mid ;
        if(bees[start.st][start.nd] <= mid){
            r = mid - 1;
            continue;
        }
        queue<pair<int,int>> q;
        q.push({start.st, start.nd});
        while(!q.empty()){
            pair<int, int> u = q.front();
            q.pop();
            for(int i = 0; i < 4; i++){
                if(!valid(u.st + dx[i], u.nd + dy[i])) continue;
                if(h[u.st][u.nd] + 1 < bees[u.st + dx[i]][u.nd + dy[i]] && 
                            h[u.st][u.nd] + 1 < h[u.st + dx[i]][u.nd + dy[i]]){
                    q.push({u.st + dx[i], u.nd + dy[i]});
                    h[u.st + dx[i]][u.nd + dy[i]] = h[u.st][u.nd] + 1;
                }
            }
        }
        if(h[finish.st][finish.nd] < INT_MAX){
            // cout << h[finish.st][finish.nd] << '\n';
            // cout << mid << ' ' << ans << '\n';
            ans = max(ans, mid);
            l = mid + 1;
        }
        else r = mid - 1;
    }
    // cout << ans << '\n';
    if(ans == -1){
        cout << -1<< '\n';
    }
    else
     cout << ans / s << '\n';

    // cout << -1 /3 << '\n';
}
 
 
int main()
{   
    // ios_base::sync_with_stdio(0); cin.tie(0); cout << fixed  << (setprecision(10)); 
    // int t;
    // cin >> t;
    // while(t--)
        solve();
    return 0;
}

• Subtask 1: 100 / 100