Submission #126529

#	Time	Username	Problem	Language	Result	Execution time	Memory
126529		khulegub	Mecho (IOI09_mecho)	C++14	62 / 100	163 ms	5112 KiB

mecho

#include <bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define xx first
#define yy second
using namespace std;
typedef long long i64;
typedef pair<int,int> pii;
int n;
int s;
char gazar[810][810];
bool vis[810][810];
int beed[810][810];
int mei, mej;
bool feasible (int x){
	memset(vis, 0, sizeof vis);
	queue<pii> q;
	int depth = x * s;
	q.push(mp(mei, mej));
	vis[mei][mej] = 1;
	while(!q.empty()){
		int sz = q.size();
		for (int cnt = 0; cnt < sz; cnt++){
			pii nw = q.front();
			if (gazar[nw.xx][nw.yy] == 'D') return 1;
			q.pop();
			if (nw.xx < n && !vis[nw.xx + 1][nw.yy] && (gazar[nw.xx + 1][nw.yy] == 'D' || (gazar[nw.xx + 1][nw.yy] == 'G' && ((depth+1) / s) < beed[nw.xx + 1][nw.yy]) ) ) q.push(mp(nw.xx + 1, nw.yy)), vis[nw.xx + 1][nw.yy] = 1;
			if (nw.xx > 1 && !vis[nw.xx - 1][nw.yy] && (gazar[nw.xx - 1][nw.yy] == 'D' || (gazar[nw.xx - 1][nw.yy] == 'G' && ((depth+1) / s) < beed[nw.xx - 1][nw.yy]) ) ) q.push(mp(nw.xx - 1, nw.yy)), vis[nw.xx - 1][nw.yy] = 1;
			if (nw.yy < n && !vis[nw.xx][nw.yy + 1] && (gazar[nw.xx][nw.yy + 1] == 'D' || (gazar[nw.xx][nw.yy + 1] == 'G' && ((depth+1) / s) < beed[nw.xx][nw.yy + 1]) ) ) q.push(mp(nw.xx, nw.yy + 1)), vis[nw.xx][nw.yy + 1] = 1;
			if (nw.yy > 1 && !vis[nw.xx][nw.yy - 1] && (gazar[nw.xx][nw.yy - 1] == 'D' || (gazar[nw.xx][nw.yy - 1] == 'G' && ((depth+1) / s) < beed[nw.xx][nw.yy - 1]) ) ) q.push(mp(nw.xx, nw.yy - 1)), vis[nw.xx][nw.yy - 1] = 1;
		}
		depth ++;
	}
	return 0;
}
int main (){
	ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	// freopen("in.txt", "r", stdin);
	cin >> n;
	cin >> s;
	for (int i = 1; i <= n; i++){
		string tmp;
		cin >> tmp;
		// cout << tmp;
		for (int j = 1; j <= n; j++){
			gazar[i][j] = tmp[j - 1];
			if (tmp[j - 1] == 'M') mei = i, mej = j;
		}
	}

	queue<pii> q;
	for (int i = 1; i <= n; i++){
		for (int j = 1; j <= n; j++){
			if (gazar[i][j] == 'H') q.push( mp(i, j) ), vis[i][j] = 1;
		}
	}
	int depth = 0;
	// cout << "QQQ";
	while (!q.empty()){
		int sz = q.size();
		// cout << sz << ' ';
		for (int cnt = 0; cnt < sz; cnt++){
			pii nw = q.front();
			q.pop();
			beed[nw.xx][nw.yy] = depth;
			if (nw.xx < n && !vis[nw.xx + 1][nw.yy] && (gazar[nw.xx + 1][nw.yy] == 'M' || gazar[nw.xx + 1][nw.yy] == 'G') ) q.push(mp(nw.xx + 1, nw.yy)), vis[nw.xx + 1][nw.yy] = 1;
			if (nw.xx > 1 && !vis[nw.xx - 1][nw.yy] && (gazar[nw.xx - 1][nw.yy] == 'M' || gazar[nw.xx - 1][nw.yy] == 'G') ) q.push(mp(nw.xx - 1, nw.yy)), vis[nw.xx - 1][nw.yy] = 1;
			if (nw.yy < n && !vis[nw.xx][nw.yy + 1] && (gazar[nw.xx][nw.yy + 1] == 'M' || gazar[nw.xx][nw.yy + 1] == 'G') ) q.push(mp(nw.xx, nw.yy + 1)), vis[nw.xx][nw.yy + 1] = 1;
			if (nw.yy > 1 && !vis[nw.xx][nw.yy - 1] && (gazar[nw.xx][nw.yy - 1] == 'M' || gazar[nw.xx][nw.yy - 1] == 'G') ) q.push(mp(nw.xx, nw.yy - 1)), vis[nw.xx][nw.yy - 1] = 1;
		}
		depth++;
	}
	int lo = 0, hi = beed[mei][mej] - 1;
	while (lo + 1 < hi){
		int mid = (lo + hi) >> 1;
		if (feasible(mid)) lo = mid;
		else hi = mid - 1;
	}
	if(feasible(lo)) cout << lo;
	else cout << -1;
	return 0;
}

• Subtask 1: 62 / 100