Submission #1072008

#	Time	Username	Problem	Language	Result	Execution time	Memory
1072008		7again	Mecho (IOI09_mecho)	C++17	14 / 100	369 ms	12320 KiB

mecho

#include <bits/stdc++.h>

using namespace std ;

const int N = 800 ;
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] != 'T') ;
}
bool val(int x , int y) {
    return  x / s < y ;
}
bool ok(int time) {

    vector<vector<int>> mn2(N , vector<int>(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}) ;
            }
        }
    }

    vector<vector<int>> mn(N , vector<int>(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}) ;
            }
        }
    }
    if(mn[Home.first][Home.second] == 1e9)
        return  0 ;
    return  1 ;
}
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 + 1 < r) {
        int m = (l + r) / 2 ;
        if(ok(m))
            l = m ;
        else
            r = m ;
    }
    cout << l << endl ;
}
void z() {
    int n , m ;
    cin >> n >> m ;
    int a[2 * n][m] ;
    for(int i = 0 ; i < 2 * n ; i += 2) {
        for(int j = 0 ; j < m ; j++) {
            cin >> a[i][j] ;
            a[i + 1][j] = a[i][j] ;
        }
    }
}

• Subtask 1: 14 / 100