Submission #558333

#	Time	Username	Problem	Language	Result	Execution time	Memory
558333		Cookie	Mecho (IOI09_mecho)	C++14	100 / 100	182 ms	7388 KiB

mecho

#include <bits/stdc++.h>
using namespace std;
#define LIFESUCKS ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define ll long long
#define ld long double
#define ar array
#include<cstdio>
#define vt vector
#include<fstream>
ifstream fin("piggyback.in");
ofstream fout("piggyback.out");
#include<fstream>
#define pb push_back
#define all(c) (c).begin(), (c).end()

#define fi first
#define se second
#define vt vector
using namespace std;
int n, s, sti, stj, eni, enj;
bool vis[801][801];
int dis[801][801];
int dis2[801][801];
char a[801][801];
bool bee = true;
const int x[4] = {1, -1, 0, 0};
const int y[4] = {0, 0, 1, -1};
bool check(int mid){
    memset(vis, false, sizeof(vis));
    memset(dis2, false, sizeof(dis2));
    queue<pair<int, int>>q;
    q.push({sti, stj});
    vis[sti][stj] = true;
    if(mid >= dis[sti][stj])return(false);
    dis2[sti][stj] = 0;
    while(!q.empty()){
        auto now = q.front(); q.pop();
        //cout << "mm";
        for(int i = 0; i < 4; i++){
            int cri = now.fi + x[i];
            int crj = now.se + y[i];
            if(cri < 0 || crj < 0 || cri >= n || crj >= n)continue;
            if(!vis[cri][crj] &&(a[cri][crj] == 'G' || a[cri][crj] == 'D' || a[cri][crj] == 'M')){
               // cout << "lol";
                if(dis[cri][crj] > floor((double)(dis2[now.fi][now.se] + 1) / (double)s) + mid){
                    vis[cri][crj] = true;
                    dis2[cri][crj] = dis2[now.fi][now.se] + 1;
                    if(a[cri][crj] == 'D')return(true);
                    q.push({cri, crj});
                }
            }
        }
    }
    //cout << "\n";
    return(false);
}
void bfs(){
    memset(vis, false, sizeof(vis));
    
    queue<pair<int, int>>q;
    
    for(int i = 0; i < n; i++){
        for(int j = 0; j < n; j++){
            if(a[i][j] == 'H'){
                q.push({i, j});
                vis[i][j] = true;
                dis[i][j] = 0;
            }
        }
    }
    while(!q.empty()){
        
        auto now = q.front(); q.pop();
        for(int i = 0; i < 4; i++){
            int cri = now.fi + x[i];
            int crj = now.se + y[i];
            if(cri < 0 || crj < 0 || cri >= n || crj >= n)continue;
            if(!vis[cri][crj] && (a[cri][crj] == 'G' || a[cri][crj] == 'H' || a[cri][crj] == 'M')){
                vis[cri][crj] = true;
                dis[cri][crj] = dis[now.fi][now.se] + 1;
                q.push({cri, crj});
            }
        }
    }
    
}
int main(){
    LIFESUCKS;
   cin >> n >> s;
   
   for(int i = 0; i < n; i++){
       for(int j = 0; j < n; j++){
           dis[i][j] = 1e9;
           cin >> a[i][j];
           if(a[i][j] == 'M'){
               sti = i, stj = j;
           }if(a[i][j] == 'D'){
               eni = i; enj = j;
           }
       }
   }
   //cout << sti << ' ' << stj << " ";
   bfs();
   
   int l = 0;
   int r = 1e9;
   int ans = -1;
   while(l <= r){
       int mid = l + (r - l) / 2;
       if(check(mid)){
           ans = mid; l = mid + 1;
       }else{
           r = mid - 1;
       }
   }
   cout << ans;
    return 0;
}

• Subtask 1: 100 / 100