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| #include <iostream>
#include <tuple>
#include <vector>
#include <algorithm>
#include <queue>
#define maxn 10010
#define maxm 110
#define INF 1000000000
#define ll long long
using namespace std;
int dx[] = { 0, 0, 1, -1 };
int dy[] = { 1, -1, 0, 0 };
int n, m, a[maxm][maxm], b[maxm][maxm];
char str[maxn];
int id[maxm][maxm], cnt, w[maxn];
void bfs(int sx, int sy) {
queue<pair<int, int>> Q; Q.push({ sx, sy });
id[sx][sy] = ++cnt;
while (!Q.empty()) {
int i = Q.front().first, j = Q.front().second; Q.pop();
w[cnt] += a[i][j] == b[i][j] ? -1 : 1;
for (int k = 0; k < 4; ++k) {
int x = i + dx[k], y = j + dy[k];
if (x < 1 || x > n || y < 1 || y > m) continue;
if (id[x][y] || a[x][y] != a[i][j]) continue;
id[x][y] = cnt; Q.push({ x, y });
}
}
}
vector<int> G[maxn]; int col[maxn];
void dfs(int u) {
for (int v : G[u])
if (!col[v]) col[v] = col[u] * -1, dfs(v);
}
struct Edge {
int to, next, w;
} e[1000000]; int c1, head[maxn];
inline void add_edge(int u, int v, int w) {
e[c1].to = v; e[c1].w = w;
e[c1].next = head[u]; head[u] = c1++;
}
inline void Add_edge(int u, int v, int w) {
add_edge(u, v, w); add_edge(v, u, 0);
}
int dep[maxn], s, t;
bool bfs() {
queue<int> Q; Q.push(s);
fill(dep, dep + maxn, 0); dep[s] = 1;
while (!Q.empty()) {
int u = Q.front(); Q.pop();
for (int i = head[u]; ~i; i = e[i].next) {
int v = e[i].to, w = e[i].w;
if (w > 0 && !dep[v]) {
dep[v] = dep[u] + 1;
Q.push(v); if (v == t) return 1;
}
}
} return 0;
}
int dfs(int u, int _w) {
if (!_w || u == t) return _w;
int s = 0;
for (int i = head[u]; ~i; i = e[i].next) {
int v = e[i].to, w = e[i].w;
if (w > 0 && dep[v] == dep[u] + 1) {
int di = dfs(v, min(_w - s, w));
e[i].w -= di; e[i ^ 1].w += di;
s += di; if (s == _w) break;
}
}
if (s < _w) dep[u] = 0;
return s;
}
int dinic() {
int mf = 0;
while (bfs()) mf += dfs(s, INF);
return mf;
}
int main() { fill(head, head + maxn, -1);
ios::sync_with_stdio(false);
cin.tie(nullptr); cout.tie(nullptr);
cin >> n >> m; int ans = 0;
for (int i = 1; i <= n; ++i) {
cin >> str + 1;
for (int j = 1; j <= m; ++j) a[i][j] = str[j] == '1';
}
for (int i = 1; i <= n; ++i) {
cin >> str + 1;
for (int j = 1; j <= m; ++j) b[i][j] = str[j] == '1', ans += a[i][j] == b[i][j];
}
for (int i = 1; i <= n; ++i)
for (int j = 1; j <= m; ++j) if (!id[i][j]) bfs(i, j);
for (int i = 1; i <= n; ++i)
for (int j = 1; j <= m; ++j)
for (int k = 0; k < 4; ++k) {
int x = i + dx[k], y = j + dy[k];
if (x < 1 || x > n || y < 1 || y > m) continue;
if (id[x][y] == id[i][j]) continue;
G[id[i][j]].push_back(id[x][y]);
}
col[1] = 1; dfs(1); s = 0; t = cnt + 1;
for (int u = 1; u <= cnt; ++u) {
if (col[u] == 1) Add_edge(s, u, w[u]), ans += max(0, w[u]);
else Add_edge(u, t, w[u]), ans += max(0, w[u]);
if (col[u] == 1) for (int v : G[u]) Add_edge(u, v, INF);
} cout << n * m - (ans - dinic()) << "\n";
return 0;
}
|