#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <string>
#include <cmath>
#include <cstdio>
#include <iomanip>
#include <fstream>
#include <cassert>
#include <cstring>
#include <unordered_set>
#include <unordered_map>
#include <numeric>
#include <ctime>
#include <bitset>
#include <complex>
#include <random>
using namespace std;
struct Edge {
int u, v;
int cap, flow;
Edge(int u_, int v_, int flow_, int cap_) {
u = u_;
v = v_;
cap = cap_;
flow = flow_;
}
};
namespace Flow {
const int INF = 1e9 + 239;
const int MAX_LOG = 2;
int n;
int start;
int end;
vector<int> d;
vector<int> pnt;
vector<Edge> ed;
vector<vector<int>> g;
int dfs(int u, int flow) {
if (flow == 0) {
return 0;
}
if (u == end) {
return flow;
}
for (; pnt[u] < (int)g[u].size(); pnt[u]++) {
int ind = g[u][pnt[u]];
int to = ed[ind].v;
if (d[to] < d[u] + 1) {
continue;
}
int pushed = dfs(to, min(flow, ed[ind].cap - ed[ind].flow));
if (pushed > 0) {
ed[ind].flow += pushed;
ed[ind ^ 1].flow -= pushed;
return pushed;
}
}
return 0;
}
bool bfs(int lim) {
for (int i = 0; i < n; i++) {
d[i] = INF;
}
d[start] = 0;
queue<int> q;
q.push(start);
while (!q.empty()) {
int u = q.front();
q.pop();
for (auto ind : g[u]) {
int to = ed[ind].v;
if (d[to] > d[u] + 1 && ed[ind].flow + lim <= ed[ind].cap) {
d[to] = d[u] + 1;
q.push(to);
}
}
}
return d[end] != INF;
}
void init() {
pnt.resize(n, false);
d.resize(n);
g.resize(n);
}
int solve() {
int ans = 0;
int cur = (1LL << MAX_LOG);
for (int i = 0; i < MAX_LOG; i++) {
cur /= 2;
while (bfs(cur)) {
fill(pnt.begin(), pnt.end(), 0);
while (true) {
int nw = dfs(start, INF);
ans += nw;
if (nw == 0) {
break;
}
}
}
}
return ans;
}
void add_edge(int u, int v, int c) {
int pnt = (int)ed.size();
ed.push_back(Edge(u, v, 0, c));
ed.push_back(Edge(v, u, 0, 0));
g[u].push_back(pnt);
g[v].push_back(pnt + 1);
}
}// namespace Flow
const int N = 3001;
int a[N][N];
int read() {
char c;
cin >> c;
if (c == 'R') return 0;
if (c == 'G') return 1;
if (c == 'W') return 2;
assert(false);
return -1;
}
int n, m;
int ok(int i, int j, int dir) {
if (dir == 0) {
if (i == 0 || i + 1 == n) return 0;
return a[i - 1][j] == 0 && a[i][j] == 1 && a[i + 1][j] == 2;
} else {
if (j == 0 || j + 1 == m) return 0;
return a[i][j - 1] == 0 && a[i][j] == 1 && a[i][j + 1] == 2;
}
}
vector<pair<int, int>> gt(int i, int j, int dir) {
if (dir == 0) {
return {{i - 1, j}, {i, j}, {i + 1, j}};
} else {
return {{i, j - 1}, {i, j}, {i, j + 1}};
}
}
bool inter(vector<pair<int, int>> &x, vector<pair<int, int>> &y) {
for (auto f : x) {
for (auto s : y) {
if (f == s) return 1;
}
}
return 0;
}
vector<vector<int>> g;
int used[N * N];
int clr[N * N];
int mt[N * N];
void dfs(int v, int c) {
clr[v] = c;
used[v] = 1;
for (auto t : g[v]) {
if (!used[t]) dfs(t, c ^ 1);
}
}
int sm(int v, int timer) {
if (used[v] == timer) return 0;
used[v] = timer;
for (auto t : g[v]) {
if (mt[t] == -1 || sm(mt[t], timer)) {
mt[t] = v;
return 1;
}
}
return 0;
}
void dfs2(int v) {
used[v] = 1;
for (auto t : g[v]) {
if (mt[t] == v) continue;
used[t] = 1;
if (mt[t] != -1 && !used[mt[t]]) dfs2(mt[t]);
}
}
void init_matching(int f) {
Flow::n = f + 2;
Flow::end = f + 1;
Flow::start = f;
Flow::init();
cerr << "flow init ok" << endl;
vector<int> we(f);
for (int i = 0; i < f; i++) {
for (auto j : g[i]) {
if (!clr[i]) {
Flow::add_edge(i, j, 1);
if (!we[i]) Flow::add_edge(f, i, 1);
we[i] = 1;
if (!we[j]) Flow::add_edge(j, f + 1, 1);
we[j] = 1;
}
}
}
cerr << "flow kek " << endl;
Flow::solve();
cerr << "flow lol" << endl;
fill(mt, mt + f, -1);
for (auto t : Flow::ed) {
if (t.flow == 1 && t.v < f && t.u < f) {
mt[t.v] = t.u;
}
}
}
int solve_mathing() {
int f = (int)g.size();
for (int i = 0; i < f; i++) {
if (!used[i]) dfs(i, 0);
}
init_matching(f);
fill(used, used + f, 0);
vector<int> ns(f);
for (int i = 0; i < f; i++) {
if (mt[i] != -1) {
ns[mt[i]] = 1;
}
}
for (int i = 0; i < f; i++) {
if (!clr[i] && !ns[i]) {
dfs2(i);
}
}
int ans = 0;
for (int i = 0; i < f; i++) {
ans += (used[i] && !clr[i]);
}
for (int i = 0; i < f; i++) {
ans += (!used[i] && clr[i]);
}
return ans;
}
vector<int> cd[N][N];
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cin >> n >> m;
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
a[i][j] = read();
}
}
vector<int> tk;
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
if (ok(i, j, 0)) {
tk.push_back({i * m + j});
cd[i][j].push_back((int)tk.size() - 1);
}
if (ok(i, j, 1)) {
tk.push_back({i * m + j + n * m});
cd[i][j].push_back((int)tk.size() - 1);
}
}
}
auto get = [&](int x) {
int v = tk[x];
int tp = (v / (n * m));
v %= n * m;
int i = v / m;
int j = v % m;
return gt(i, j, tp);
};
g.resize(tk.size());
for (int i = 0; i < (int)tk.size(); i++) {
int v = (tk[i] % (n * m));
int ri = v / m;
int rj = v % m;
for (int ti = ri - 1; ti <= ri + 1; ti++) {
for (int tj = rj - 1; tj <= rj + 1; tj++) {
if (ti < 0 || tj < 0 || ti >= n || tj >= m) continue;
for (auto j : cd[ti][tj]) {
if (i == j) continue;
vector<pair<int, int>> f = get(i);
vector<pair<int, int>> s = get(j);
if (inter(f, s)) {
g[i].push_back(j);
}
}
}
}
}
cout << solve_mathing() << endl;
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
131 ms |
211832 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
131 ms |
211832 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
131 ms |
211832 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
