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| #include <bits/stdc++.h>
#include <ext/pb_ds/priority_queue.hpp>
using namespace std;
using namespace __gnu_pbds;
#define tar(i,n) for(int i=1;i<=n;++i)
const int N = 105;
const double eps = 1e-7;
double L;
int R, C;
char mymap[N][N];
int pos[N][N];
int S, T, Tim;
typedef __gnu_pbds::priority_queue <pair<double, int>, greater<pair<double, int> >, pairing_heap_tag> heap;
struct node {
int next, to;
bool flag;
} edge[50005];
int first[10005], tot;
inline void Tjb(int x, int y, bool _flag) {
edge[++tot].to = y; edge[tot].flag = _flag;
edge[tot].next = first[x]; first[x] = tot;
}
inline void lql() {
memset(first, 0, sizeof(first)); tot = 0;
}
double Dist[10005];
inline double dijkstra(double X) {
heap q;
vector<heap::point_iterator> id;
id.reserve(1000005);
tar(i, R * C)Dist[i] = 5000.0; Dist[S] = 0.0;
q.push(make_pair(Dist[S], S));
while (!q.empty()) {
int u = q.top().second; q.pop();
for (int k = first[u]; k; k = edge[k].next) {
int v = edge[k].to;
if (edge[k].flag) {
if (Dist[v] > Dist[u] + X) {
Dist[v] = Dist[u] + X;
if (id[v] != 0)
q.modify(id[v], make_pair(Dist[v], v));
else id[v] = q.push(make_pair(Dist[v], v));
}
} else {
if (Dist[v] > Dist[u] + 1) {
Dist[v] = Dist[u] + 1;
if (id[v] != 0)
q.modify(id[v], make_pair(Dist[v], v));
else id[v] = q.push(make_pair(Dist[v], v));
}
}
}
}
return Dist[T];
}
inline void Test() {
lql();
scanf("%lf%d%d\n", &L, &R, &C);
Tim = 0;
tar(i, R) {
tar(j, C)mymap[i][j] = getchar();
scanf("\n");
}
tar(i, R)tar(j, C)if (mymap[i][j] != '#') {
pos[i][j] = ++Tim;
if (mymap[i][j] == 'S')S = pos[i][j]; else if (mymap[i][j] == 'E')T = pos[i][j];
}
tar(i, R)tar(j, C)if (mymap[i][j] != '#') {
if (i != 1 && mymap[i - 1][j] != '#')Tjb(pos[i][j], pos[i - 1][j], true);
if (i != R && mymap[i + 1][j] != '#')Tjb(pos[i][j], pos[i + 1][j], true);
if (j != 1 && mymap[i][j - 1] != '#')Tjb(pos[i][j], pos[i][j - 1], false);
if (j != R && mymap[i][j + 1] != '#')Tjb(pos[i][j], pos[i][j + 1], false);
}
double l = 0.0, r = 10.0, ans = 0.0;
while (r - l > eps) {
double mid = (l + r) / 2;
if (dijkstra(mid) < L)ans = mid, l = mid; else r = mid;
}
printf("%.5lf\n", ans);
}
int main() {
int times;
scanf("%d", ×);
while (times--)Test();
return 0;
}
|
