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| #include <bits/stdc++.h>
using namespace std;
const int N = 1e3+66;
int n, m, T;
int vis[N][N];
char ch[N][N];
int dx[5] = {0, 0, 1, -1};
int dy[5] = {1, -1, 0, 0};
struct node {int x, y;node(int x, int y):x(x), y(y){}};
inline void bfs () {
queue<node>jq, fq;
for (int i = 0; i < n; ++ i)
for (int j = 0; j < m; ++ j) {
if (ch[i][j] == 'J') {
jq.push(node(i, j));
vis[i][j] = 1;
} else if (ch[i][j] == 'F') {
fq.push(node(i, j));
ch[i][j] = '#';
}
}
int step(0);
while (jq.size()) {
++ step;
for (int i = 0, j = jq.size(); i < j; ++ i) {
node tmp = jq.front(); jq.pop();
if (ch[tmp.x][tmp.y] == '#') continue;
for (int k = 0; k < 4; ++ k) {
int nx = tmp.x+dx[k], ny = tmp.y+dy[k];
if (nx >= 0 && nx < n && ny >= 0 && ny < m) {
if (ch[nx][ny] != '#' && !vis[nx][ny])
vis[nx][ny] = 1, jq.push(node(nx, ny));
}
else {cout << step << '\n'; return;}
}
}
for (int i = 0, j = fq.size(); i < j; ++ i) {
node tmp = fq.front(); fq.pop();
for (int k = 0; k < 4; ++ k) {
int nx = tmp.x+dx[k], ny = tmp.y+dy[k];
if (nx >= 0 && nx < n && ny >= 0 && ny < m && ch[nx][ny] != '#')
ch[nx][ny] = '#', fq.push(node(nx, ny));
}
}
}
puts ("IMPOSSIBLE");
}
int main () {
cin >> T;
while (T --> 0) {
cin >> n >> m;
for (int i = 0; i < n; ++ i) scanf ("%s", ch[i]);
bfs ();
memset (vis, 0, sizeof vis);
}
return 0;
}
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