Submission #1037042

#	Time	Username	Problem	Language	Result	Execution time	Memory
1037042		hippo123	Mecho (IOI09_mecho)	C++17	64 / 100	146 ms	7252 KiB

mecho

#include <bits/stdc++.h>
 
using namespace std;
#define ll long long
#define f first
#define s second
#define pr pair<int, int>
#define pb push_back
const int ndim=800;
const int dmax=1e9; 

vector<string> mp(ndim);
vector<int> level(ndim*ndim, -1);
vector<int> level2(ndim*ndim, -1);

int dx[4]={1, -1, 0, 0};
int dy[4]={0, 0, 1, -1};
int n, s; 

bool dmcheck(int x, int y){
	if(x>=0 && x<n && y>=0 && y<n && mp[x][y]!='T' && mp[x][y]!='D' && level[x*n+y]==-1 ) return true;
	else return false;
}

bool bearcheck(int x, int y){
	if(x>=0 && x<n && y>=0 && y<n && mp[x][y]!='T' && mp[x][y]!='H' && level2[x*n+y]==-1 ) return true;
	else return false;

}

bool check(int mid, pr M, pr hs){
	
	for (int i=0; i<n*n; i++) level2[i]=-1;
	
	queue<pr> q; 
	q.push({M.f*n+M.s, 0});
	level2[M.f*n+M.s]=0;
	bool judge=false; 
	while(!q.empty()){
		pr n1=q.front(); q.pop();
		int nd=n1.f; int lev=n1.s; 
		int x=nd/n; int y=nd%n;
		//cout<< "x/y= "<<x<<" "<<y<<endl;
		//cout<<" level[x*n+y]-mid= "<<level[x*n+y]-mid<<endl;
		if(lev>=(level[x*n+y]-mid)*s) continue; 
		
		
		for (int i=0; i<4; i++){
			int x2=x+dx[i]; int y2=y+dy[i];
			
			if( bearcheck(x2, y2)){
				//cout<<" x2/y2= "<<x2<<" "<<y2<< "hs= "<<hs.f<<" "<<hs.s<<endl;
				if(x2==hs.f && y2==hs.s ){ judge=true; break;}
				//cout<<" lev+1 / (level[x2*n+y2]-mid)*s= "<<lev+1 <<" "<< (level[x2*n+y2]-mid)*s<<endl;
				if(lev+1 <= (level[x2*n+y2]-mid)*s){ // level is bee
					q.push({x2*n+y2, lev+1});
					level2[x2*n+y2]= lev+1;
				}
				
				
			}
			if(judge) break; 
		}	
		if(judge) break; 
	}

	//for (int i=0; i<n; i++){
	//	for (int j=0; j<n; j++) cout<<level2[i*n+j]<<" ";
	//	cout<<endl;
	//}	
	
	
	//cout<<" judge= "<<judge<<endl;
	return judge;
	
}


int main(){
	cin>>n>>s; 
	vector<pr> hv;
	pr M, hs;	
	for (int i=0; i<n; i++) {
		cin>>mp[i]; 
		for (int j=0; j<n; j++){
			if(mp[i][j]=='H') hv.pb({i, j});
			if(mp[i][j]=='M') M={i, j};
			if(mp[i][j]=='D') hs={i, j};
		}
	}
	//cout<<" hs= "<<hs.f<<" "<<hs.s<<endl;
	queue<pr> q; 

	for (auto elem: hv) {
		q.push({elem.f*n+elem.s, 0});
		level[elem.f*n+elem.s]=0;
	}
	while (!q.empty()){
		pr n1=q.front(); q.pop();
		
		int nd=n1.f; int lev=n1.s;
		int x=nd/n; int y=nd%n;
		
		for (int i=0; i<4; i++){
			int x2=x+dx[i]; int y2=y+dy[i];
			if(dmcheck(x2, y2)){
				q.push({x2*n+y2, lev+1}); level[x2*n+y2]=lev+1; 
			}
		}		
	}
	//for (int i=0; i<n; i++){
	//	for (int j=0; j<n; j++) cout<<level[i*n+j]<<" ";
	//	cout<<endl;
	//}
	
	int lft=0; int rht=100000;
	while(lft<rht ){
		
		int mid=(rht+lft+1)/2;
	//	cout<<" lft/rht/mid= "<<lft<<" "<<rht<<" "<<mid<<endl;
		if(check(mid, M, hs)) lft=mid;
		else rht=mid-1; 
	}
	cout<<lft<<endl;
}

• Subtask 1: 64 / 100