Submission #19322

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Source Code Expand

#include <iostream>
#include <cstdio>
#include <vector>
#include <string>
#include <queue>
#include <map>
#include <set>
#include <cmath>
using namespace std;

const int di[] = {+1,-1, 0, 0};
const int dj[] = { 0, 0,+1,-1};

int N, M;
vector<string> s;
bool visited[500][500];

bool visit(int i, int j) {
	if (!(0 <= i && i < N && 0 <= j && j < M)) return false;
	if (s[i][j] == '#') return false;
	if (s[i][j] == 'g') return true;
	if (visited[i][j]) return false;
	visited[i][j] = true;
	for (int k = 0; k < 4; ++ k) {
		if (visit(i+di[k], j+dj[k])) return true;
	}
	return false;
}

int main() {
	cin >> N >> M;
	s= vector<string>(N);
	int si = 0, sj = 0;
	int gi = 0, gj = 0;
	for (int i = 0; i < N; ++ i) {
		cin >> s[i];
		for (int j = 0; j < M; ++ j) {
			if (s[i][j] == 's') {
				si = i;
				sj = j;
			}
			if (s[i][j] == 'g') {
				gi = i;
				gj = j;
			}
		}
	}
	if (!visit(si, sj)) {
		cout << -1 << endl;
		return 0;
	}
	vector<vector<double> > a(N, vector<double>(M, 0));
	a[si][sj] = 1e+300;
	set<pair<int,int> > b;
	b.insert(make_pair(si,sj));
	double ans = 0;
	for (int t = 1; !b.empty(); ++ t) {
		vector<vector<double> > a0 = a;
		set<pair<int,int> > c;
		for (set<pair<int,int> >::iterator it = b.begin(); it != b.end(); ++ it) {
			int i = it->first;
			int j = it->second;
			for (int k = 0; k < 4; ++ k) {
				int ii = i + di[k];
				int jj = j + dj[k];
				if (!(0 <= ii && ii < N && 0 <= jj && jj < M)) continue;
				if (s[ii][jj] == '#') continue;
				double x = a0[i][j];
				if ('1' <= s[ii][jj] && s[ii][jj] <= '9') {
					x = min(x, (s[ii][jj]-'0')*pow(0.99, t));
				}
				if (x > a[ii][jj]) {
					a[ii][jj] = x;
					if (x >= ans) c.insert(make_pair(ii, jj));
				}
			}
		}
		ans = max(ans, a[gi][gj]);
		b.swap(c);
	}
	printf("%.10f\n", ans);
}

Submission Info

Judge Result