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| #include <bits/stdc++.h>
using namespace std;
#define FOR(i, a, b) for (int i = a; i < b; ++i)
#define CLR(c) memset(c, 0, sizeof(c))
static auto __ = []
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
return 0;
}();
template <typename T>
T QPOP(queue<T>& q)
{
T tmp = q.front();
q.pop();
return tmp;
}
const int INF = (int)1e9;
const int MXN = 2000;
const int D[] = { 1, 0, -1, 0, 1 };
vector<int> e[MXN];
map<pair<int, int>, int> pb, po;
char g[50][50];
int dist[50][50];
int c[MXN][MXN];
int f[MXN][MXN];
int cost[MXN][MXN];
int d[MXN];
int p[MXN];
bool inQ[MXN];
int S, T;
int X, Y;
void addEdge(int u, int v, int Cap = 0, int Cost = 0)
{
e[u].push_back(v);
c[u][v] = Cap;
cost[u][v] = Cost;
}
void init()
{
for (auto& v : e) v.clear();
pb.clear();
po.clear();
CLR(f);
}
void read()
{
cin >> Y >> X;
FOR(i, 0, Y) FOR(j, 0, X)
{
cin >> g[i][j];
if (g[i][j] == 'B') pb[{i, j}] = pb.size() + 1;
else if (g[i][j] == 'X') po[{i, j}] = po.size() + 1;
}
T = pb.size() + po.size() + 1;
}
void bfs(int y, int x)
{
fill(dist[0], dist[0] + 50 * 50, INF);
dist[y][x] = 0;
queue<pair<int, int>> q;
q.push({ y, x });
while (!q.empty())
{
auto [_y, _x] = QPOP(q);
FOR(i, 0, 4)
{
int dy = _y + D[i], dx = _x + D[i + 1];
if (dy < 0 || dy >= Y || dx < 0 || dx >= X || g[dy][dx] == '#') continue;
if (dist[dy][dx] == INF) q.push({ dy, dx });
dist[dy][dx] = min(dist[_y][_x] + 1, dist[dy][dx]);
}
}
}
void build()
{
for (auto& [boxPos, u] : pb)
{
auto& [y, x] = boxPos;
bfs(y, x);
addEdge(S, u, 1);
addEdge(u, S);
for (auto [pos, v] : po)
{
auto& [dy, dx] = pos;
v += pb.size();
addEdge(u, v, 1, dist[dy][dx]);
addEdge(v, u);
}
}
for (auto [_, v] : po)
{
v += pb.size();
addEdge(v, T, 1, 0);
addEdge(T, v);
}
}
bool SPFA()
{
fill(d, d + MXN, INF);
d[S] = 0;
CLR(inQ);
queue<int> q;
q.push(S);
inQ[S] = true;
while (!q.empty())
{
auto u = QPOP(q);
inQ[u] = false;
for (auto& v : e[u])
{
if (c[u][v] > f[u][v] && d[u] + cost[u][v] < d[v])
{
d[v] = d[u] + cost[u][v];
p[v] = u;
if (!inQ[v]) q.push(v), inQ[v] = true;
}
if (f[v][u] > 0 && d[u] + (-cost[v][u]) < d[v])
{
d[v] = d[u] + (-cost[v][u]);
p[v] = u;
if (!inQ[v]) q.push(v), inQ[v] = true;
}
}
}
return d[T] != INF;
}
int augment(int u, int v, int bottleNeck)
{
if (v == S) return bottleNeck;
bottleNeck = augment(p[u], u, min(c[u][v] - f[u][v], bottleNeck));
f[u][v] += bottleNeck;
f[v][u] -= bottleNeck;
return bottleNeck;
}
int MCMF()
{
int mnC = 0, mf = 0;
while (SPFA())
{
mnC += d[T];
mf += augment(p[T], T, INF);
}
return mnC;
}
void solve()
{
build();
cout << MCMF() << '\n';
}
int main()
{
int T;
cin >> T;
while (T--)
{
init();
read();
solve();
}
}
|
