제출 #1072176

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1072176		7again	Mecho (IOI09_mecho)	C++17	90 / 100	404 ms	12624 KiB

mecho

#include <bits/stdc++.h>

using namespace std ;

const int N = 801 ;
int dx[]{0 , 0 , 1 , -1} ;
int dy[]{1 , -1 , 0 , 0} ;


int n , s ;
pair <int , int> Honey , Home ;
char a[N][N] ;

bool inside(int x , int y) {
    return (x >= 0 && y >= 0 && x < n && y < n && (a[x][y] == 'G' || a[x][y] == 'M')) ;
}
bool val(int x , int y) {
    return  x / s < y ;
}
int ok(int time) {

    int mn2[n][n] ;
    fill_n(&mn2[0][0] , n*n , 1e9) ;
    queue<pair <int , int>>  q2 ;
    for(int i = 0 ; i < n ; i++) {
        for(int j = 0 ; j < n ; j++) {
            if(a[i][j] == 'H') {
                q2.push({i, j}) ;
                mn2[i][j] = 0 ;
            }
        }
    }
    while(q2.size()) {
        pair <int , int> t = q2.front() ;
        q2.pop() ;
        for(int i = 0 ; i < 4 ; i++) {
            int x = t.first + dx[i] ;
            int y = t.second + dy[i] ;
            if(inside(x , y) &&  mn2[t.first][t.second] + 1 < mn2[x][y]) {
                mn2[x][y] = mn2[t.first][t.second] + 1 ;
                q2.push({x, y}) ;
            }
        }
    }

    int mn[n][n] ;
    fill_n(&mn[0][0] , n * n , 1e9 ) ;
    queue <pair <int , int>> q ;
    mn[Honey.first][Honey.second] = 0 ;
    if(mn2[Honey.first][Honey.second] > time)
        q.push(Honey) ;
    while(!q.empty()) {
        pair <int , int> t = q.front() ;
        q.pop() ;
        for(int i = 0 ; i < 4 ; i++) {
            int x = t.first + dx[i] ;
            int y = t.second + dy[i] ;
            if(val(mn[t.first][t.second] + 1 , mn2[x][y] - time) && inside(x , y) && mn[t.first][t.second] + 1 < mn[x][y]) {
                mn[x][y] = mn[t.first][t.second] + 1 ;
                q.push({x , y}) ;
            }
        }
    }
    for(int i = 0 ; i < 4 ; i++){
        int x = Home.first + dx[i] ;
        int y = Home.second + dy[i] ;
        if(inside(x , y) && val(mn[x][y] , mn2[x][y]  - time))
            return true ;
    }

    return  false ;
}
int main() {
    cin >> n >> s ;

    for(int i = 0 ; i < n ; i++) {
        for(int j = 0 ; j < n ; j++) {
            cin >> a[i][j] ;
            if(a[i][j] == 'M')
                Honey = {i , j} ;
            if(a[i][j] == 'D')
                Home = {i , j} ;
        }
    }

    int l = 0 , r = n * n + 1 ;
    while(l <= r) {
        int m = (l + r) / 2 ;
        if(ok(m))
            l = m + 1 ;
        else
            r = m - 1 ;
    }
    cout << l - 1 << endl ;
}

• Subtask 1: 90 / 100