mirror of
https://git.sb/baoshuo/OI-codes.git
synced 2024-11-08 15:18:46 +00:00
1189. [HNOI2007] 紧急疏散 evacuate
https://hydro.ac/d/bzoj/record/63be7bb2f49f999f0bd5ce5e
This commit is contained in:
parent
70a64a27eb
commit
448433277e
211
BZOJ/1189/1189.cpp
Normal file
211
BZOJ/1189/1189.cpp
Normal file
@ -0,0 +1,211 @@
|
||||
#include <iostream>
|
||||
#include <algorithm>
|
||||
#include <cstring>
|
||||
#include <iterator>
|
||||
#include <queue>
|
||||
|
||||
using std::cin;
|
||||
using std::cout;
|
||||
const char endl = '\n';
|
||||
|
||||
const int N = 25,
|
||||
M = N * N,
|
||||
E = 3e5 + 5;
|
||||
const int INF = 0x3f3f3f3f;
|
||||
|
||||
const int d[][2] = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
|
||||
|
||||
int n, m, s, t, cnt, f[M][M];
|
||||
char g[N][N];
|
||||
int idx, head[E], ver[E << 1], edge[E << 1], next[E << 1];
|
||||
int cur[E << 1], dist[E << 1];
|
||||
bool vis[E << 1], vis2[M][M];
|
||||
|
||||
int id(int x, int y) {
|
||||
return (x - 1) * m + y;
|
||||
}
|
||||
|
||||
void add(int u, int v, int w) {
|
||||
next[idx] = head[u];
|
||||
ver[idx] = v;
|
||||
edge[idx] = w;
|
||||
head[u] = idx++;
|
||||
}
|
||||
|
||||
bool bfs() {
|
||||
std::fill(std::begin(dist), std::end(dist), 0);
|
||||
|
||||
std::queue<int> q;
|
||||
|
||||
q.emplace(s);
|
||||
dist[s] = 1;
|
||||
cur[s] = head[s];
|
||||
|
||||
while (!q.empty()) {
|
||||
int u = q.front();
|
||||
q.pop();
|
||||
|
||||
for (int i = head[u]; ~i; i = next[i]) {
|
||||
int v = ver[i],
|
||||
w = edge[i];
|
||||
|
||||
if (!dist[v] && w) {
|
||||
dist[v] = dist[u] + 1;
|
||||
cur[v] = head[v];
|
||||
|
||||
if (v == t) return true;
|
||||
|
||||
q.emplace(v);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
int dinic(int u, int limit) {
|
||||
if (u == t) return limit;
|
||||
|
||||
int flow = 0;
|
||||
|
||||
for (int i = cur[u]; ~i && flow < limit; i = next[i]) {
|
||||
cur[u] = i;
|
||||
|
||||
int v = ver[i],
|
||||
w = edge[i];
|
||||
|
||||
if (dist[v] == dist[u] + 1 && w) {
|
||||
int k = dinic(v, std::min(w, limit - flow));
|
||||
|
||||
if (!k) dist[v] = 0;
|
||||
|
||||
edge[i] -= k;
|
||||
edge[i ^ 1] += k;
|
||||
flow += k;
|
||||
}
|
||||
}
|
||||
|
||||
return flow;
|
||||
}
|
||||
|
||||
bool check(int x) {
|
||||
idx = 0;
|
||||
std::fill(std::begin(head), std::end(head), -1);
|
||||
|
||||
for (int i = 1; i <= n; i++) {
|
||||
for (int j = 1; j <= m; j++) {
|
||||
if (g[i][j] == '.') {
|
||||
add(s, id(i, j), 1);
|
||||
add(id(i, j), s, 0);
|
||||
} else if (g[i][j] == 'D') {
|
||||
for (int k = 0; k < x; k++) {
|
||||
add(n * m + id(i, j) * x + k, t, 1);
|
||||
add(t, n * m + id(i, j) * x + k, 0);
|
||||
}
|
||||
|
||||
for (int k = 0; k < x - 1; k++) {
|
||||
add(n * m + id(i, j) * x + k, n * m + id(i, j) * x + k + 1, INF);
|
||||
add(n * m + id(i, j) * x + k + 1, n * m + id(i, j) * x + k, 0);
|
||||
}
|
||||
|
||||
for (int p = 1; p <= n; p++) {
|
||||
for (int q = 1; q <= m; q++) {
|
||||
if (g[p][q] == '.') {
|
||||
int d = f[id(p, q)][id(i, j)];
|
||||
|
||||
if (d <= x) {
|
||||
add(id(p, q), n * m + id(i, j) * x + d - 1, INF);
|
||||
add(n * m + id(i, j) * x + d - 1, id(p, q), 0);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
int res = 0;
|
||||
|
||||
while (bfs()) {
|
||||
while (int flow = dinic(s, INF)) res += flow;
|
||||
}
|
||||
|
||||
return res == cnt;
|
||||
}
|
||||
|
||||
int main() {
|
||||
std::ios::sync_with_stdio(false);
|
||||
cin.tie(nullptr);
|
||||
|
||||
memset(f, 0x3f, sizeof(f));
|
||||
|
||||
cin >> n >> m;
|
||||
|
||||
s = 0, t = 10000;
|
||||
|
||||
for (int i = 1; i <= n; i++) {
|
||||
for (int j = 1; j <= m; j++) {
|
||||
cin >> g[i][j];
|
||||
|
||||
if (g[i][j] == '.') cnt++;
|
||||
}
|
||||
}
|
||||
|
||||
for (int i = 1; i <= n; i++) {
|
||||
for (int j = 1; j <= m; j++) {
|
||||
if (g[i][j] == 'D') {
|
||||
memset(vis2, 0x00, sizeof(vis2));
|
||||
|
||||
f[id(i, j)][id(i, j)] = 0;
|
||||
|
||||
std::queue<std::pair<int, int>> q;
|
||||
|
||||
q.emplace(i, j);
|
||||
|
||||
while (!q.empty()) {
|
||||
int x = q.front().first,
|
||||
y = q.front().second;
|
||||
q.pop();
|
||||
|
||||
for (auto d : d) {
|
||||
int xx = x + d[0],
|
||||
yy = y + d[1];
|
||||
|
||||
if (xx < 0 || xx > n || yy < 0 || yy > m || g[xx][yy] != '.' || vis2[xx][yy]) continue;
|
||||
|
||||
vis2[xx][yy] = true;
|
||||
|
||||
if (f[id(xx, yy)][id(i, j)] > f[id(x, y)][id(i, j)] + 1) {
|
||||
f[id(xx, yy)][id(i, j)] = f[id(x, y)][id(i, j)] + 1;
|
||||
|
||||
q.emplace(xx, yy);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
int l = 0,
|
||||
r = cnt,
|
||||
res = -1;
|
||||
|
||||
while (l <= r) {
|
||||
int mid = (l + r) >> 1;
|
||||
|
||||
if (check(mid)) {
|
||||
r = mid - 1;
|
||||
res = mid;
|
||||
} else {
|
||||
l = mid + 1;
|
||||
}
|
||||
}
|
||||
|
||||
if (res == -1) {
|
||||
cout << "impossible" << endl;
|
||||
} else {
|
||||
cout << res << endl;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
BIN
BZOJ/1189/data/1.in
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/1.in
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/1.out
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/1.out
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/10.in
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/10.in
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/10.out
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/10.out
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/11.in
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/11.in
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/11.out
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/11.out
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/12.in
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/12.in
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/12.out
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/12.out
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/2.in
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/2.in
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/2.out
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/2.out
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/3.in
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/3.in
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/3.out
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/3.out
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/4.in
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/4.in
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/4.out
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/4.out
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/5.in
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/5.in
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/5.out
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/5.out
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/6.in
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/6.in
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/6.out
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/6.out
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/7.in
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/7.in
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/7.out
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/7.out
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/8.in
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/8.in
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/8.out
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/8.out
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/9.in
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/9.in
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
BZOJ/1189/data/9.out
(Stored with Git LFS)
Normal file
BIN
BZOJ/1189/data/9.out
(Stored with Git LFS)
Normal file
Binary file not shown.
Loading…
Reference in New Issue
Block a user