裸的最小割然而我还是太菜了，没看见有零的格子，WA了两遍
# include <bits/stdc++.h>
# define IL inline
# define RG register
# define Fill(a, b) memset(a, b, sizeof(a))
# define Copy(a, b) memcpy(a, b, sizeof(a))
# define ID(a, b) (a - 1) * m + b
using namespace std;
typedef long long ll;
const int _(10010), __(6e6 + 10), INF(2147483647);
IL ll Read(){
RG char c = getchar(); RG ll x = 0, z = 1;
for(; c < '0' || c > '9'; c = getchar()) z = c == '-' ? -1 : 1;
for(; c >= '0' && c <= '9'; c = getchar()) x = (x << 1) + (x << 3) + (c ^ 48);
return x * z;
}
int n, m, mp[110][110], w[__], fst[_], nxt[__], to[__], cnt, S, T, lev[_], cur[_], max_flow;
int dx[] = {1, -1}, dy[] = {0, 0, 1, -1};
queue <int> Q;
IL void Add(RG int u, RG int v, RG int f){
w[cnt] = f; to[cnt] = v; nxt[cnt] = fst[u]; fst[u] = cnt++;
w[cnt] = 0; to[cnt] = u; nxt[cnt] = fst[v]; fst[v] = cnt++;
}
IL int Dfs(RG int u, RG int maxf){
if(u == T) return maxf;
RG int ret = 0;
for(RG int &e = cur[u]; e != -1; e = nxt[e]){
if(lev[to[e]] != lev[u] + 1 || !w[e]) continue;
RG int f = Dfs(to[e], min(w[e], maxf - ret));
ret += f; w[e ^ 1] += f; w[e] -= f;
if(ret == maxf) break;
}
if(!ret) lev[u] = 0;
return ret;
}
IL bool Bfs(){
Fill(lev, 0); lev[S] = 1; Q.push(S);
while(!Q.empty()){
RG int u = Q.front(); Q.pop();
for(RG int e = fst[u]; e != -1; e = nxt[e]){
if(lev[to[e]] || !w[e]) continue;
lev[to[e]] = lev[u] + 1;
Q.push(to[e]);
}
}
return lev[T];
}
int main(RG int argc, RG char* argv[]){
Fill(fst, -1); n = Read(); m = Read(); T = n * m + 1;
for(RG int i = 1; i <= n; ++i)
for(RG int j = 1; j <= m; ++j){
mp[i][j] = Read();
if(mp[i][j] == 1) Add(ID(i, j), T, INF);
if(mp[i][j] == 2) Add(S, ID(i, j), INF);
}
for(RG int i = 1; i <= n; ++i)
for(RG int j = 1; j <= m; ++j){
if(mp[i][j] == 1) continue;
for(RG int d = 0; d < 4; d++){
RG int x = i + dx[d], y = j + dy[d];
if(x < 1 || y < 1 || x > n || y > m || mp[x][y] == 2) continue;
Add(ID(i, j), ID(x, y), 1);
}
}
while(Bfs()) Copy(cur, fst), max_flow += Dfs(S, INF);
printf("%d
", max_flow);
return 0;
}