제출 #585387

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
585387		Andrei_Calota	Mecho (IOI09_mecho)	C++14	28 / 100	173 ms	6352 KiB

mecho

#include <bits/stdc++.h>

using namespace std;
const int NMAX = 8e2;
const int VISUAL = 4;

int dl[] = { -1, 0, 1,  0 };
int dc[] = {  0, 1, 0, -1 };
int n, step; int bee_dist[2 + NMAX][2 + NMAX];
char forest[2 + NMAX][2 + NMAX]; int dist[2 + NMAX][2 + NMAX];
pair<int, int> honey, house;

vector<pair<int, int>> bees;
void bee_spread () {
   queue<pair<int, int>> q;
   for ( auto pos : bees ) {
      q.push ( pos );
      bee_dist[pos.first][pos.second] = 1;
   }
   while ( !q.empty () ) {
      pair<int, int> start = q.front (); q.pop ();
      int line = start.first, column = start.second;
      for ( int dir = 0; dir < VISUAL; dir ++ ) {
         int new_line = line + dl[dir];
         int new_col = column + dc[dir];
         if ( forest[new_line][new_col] != 'T' && bee_dist[new_line][new_col] == 0 ) {
           bee_dist[new_line][new_col] = bee_dist[line][column] + 1;
           q.push ( {new_line, new_col} );
         }
      }
   }
}
bool validation ( int time, pair<int, int> start ) {
   queue<pair<int, int>> q; q.push ( start );
   dist[start.first][start.second] = 1;
   while ( !q.empty () ) {
      start = q.front (); q.pop ();
      int line = start.first, column = start.second;
      for ( int dir = 0; dir < VISUAL; dir ++ ) {
         int new_line = line + dl[dir];
         int new_col = column + dc[dir];
         if ( (forest[new_line][new_col] == 'D' || forest[new_line][new_col] == 'G') && dist[new_line][new_col] == 0 ) {
           int need = dist[line][column] / step;
           if ( need + time < bee_dist[new_line][new_col] ) {
             q.push ( {new_line, new_col} );
             dist[new_line][new_col] = dist[line][column] + 1;
           }
         }
      }
   }
   if ( dist[house.first][house.second] )
     return true;
   return false;
}

void reset_dist () {
   for ( int i = 1; i <= n; i ++ )
      for ( int j = 1; j <= n; j ++ )
         dist[i][j] = 0;
}
void solve () {
   int left = 0, right = n; int answer = -1;
   while ( left <= right ) {
      int time = left + (right - left) / 2;
      int status = validation ( time, honey );
      if ( status == true ) {
        answer = time;
        left = time + 1;
      }
      else
        right = time - 1;
      reset_dist ();
   }
   cout << answer;
}
int main()
{
   cin >> n >> step; cin.get ();
   for ( int line = 1; line <= n; line ++ ) {
      for ( int column = 1; column <= n; column ++ ) {
         forest[line][column] = cin.get ();
         if ( forest[line][column] == 'M' )
           honey = {line, column};
         else if ( forest[line][column] == 'D' )
           house = {line, column};
         else if ( forest[line][column] == 'H' )
           bees.push_back ( {line, column} );
      }
      cin.get ();
   }
   for ( int indx = 0; indx < n + 2; indx ++ ) {
      forest[indx][0] = forest[indx][n + 1] = 'T';
      forest[0][indx] = forest[n + 1][indx] = 'T';
   }
   bee_spread ();
   for ( int i = 1; i <= n; i ++ )
      for ( int j = 1; j <= n; j ++ )
         bee_dist[i][j] --;
   solve ();
    return 0;
}

• Subtask 1: 28 / 100