Submission #519445

#	Time	Username	Problem	Language	Result	Execution time	Memory
519445		AdamGS	Mecho (IOI09_mecho)	C++17	100 / 100	188 ms	6604 KiB

mecho

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#define rep(a, b) for(int a = 0; a < (b); ++a)
#define st first
#define nd second
#define pb push_back
#define all(a) a.begin(), a.end()
const int LIM=807, INF=1e9+7;
int dx[]={1, 0, -1, 0}, dy[]={0, 1, 0, -1};
string T[LIM];
int odl[LIM][LIM], wolne[LIM][LIM], n, s;
bool pole(int a, int b) {
	return 0<=a && a<n && 0<=b && b<n;
}
bool ok(int x) {
	queue<pair<int,int>>q;
	rep(i, n) rep(j, n) {
		if(T[i][j]=='M') {
			q.push({i, j});
			odl[i][j]=x*s;
		} else odl[i][j]=INF;
	}
	while(!q.empty()) {
		int a=q.front().st, b=q.front().nd; q.pop();
		if(odl[a][b]>=wolne[a][b]) continue;
		if(T[a][b]=='D') return true;
		rep(i, 4) if(pole(a+dx[i], b+dy[i])) {
			if((T[a+dx[i]][b+dy[i]]=='G' || T[a+dx[i]][b+dy[i]]=='D') && odl[a+dx[i]][b+dy[i]]==INF) {
				odl[a+dx[i]][b+dy[i]]=odl[a][b]+1;
				q.push({a+dx[i], b+dy[i]});
			}
		}
	}
	return false;
}
int main() {
	ios_base::sync_with_stdio(0); cin.tie(0);
	cin >> n >> s;
	queue<pair<int,int>>q;
	rep(i, n) {
		cin >> T[i];
		rep(j, n) {
			if(T[i][j]=='H') q.push({i, j});
			else wolne[i][j]=INF;
		}
	}
	while(!q.empty()) {
		int a=q.front().st, b=q.front().nd; q.pop();
		rep(i, 4) if(pole(a+dx[i], b+dy[i])) {
			if((T[a+dx[i]][b+dy[i]]=='G' || T[a+dx[i]][b+dy[i]]=='M') && wolne[a+dx[i]][b+dy[i]]==INF) {
				wolne[a+dx[i]][b+dy[i]]=wolne[a][b]+s;
				q.push({a+dx[i], b+dy[i]});
			}
		}
	}
	if(!ok(0)) {
		cout << -1 << '\n';
		return 0;
	}
	int p=0, k=LIM*LIM;
	while(p<k) {
		int sr=(p+k+1)/2;
		if(ok(sr)) p=sr; else k=sr-1;
	}
	cout << p << '\n';
}

• Subtask 1: 100 / 100