/
16932.cpp
149 lines (143 loc) · 4.44 KB
/
16932.cpp
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# pragma GCC optimize ("O3")
# pragma GCC optimize ("Ofast")
# pragma GCC optimize ("unroll-loops")
# pragma GCC target("sse,sse2,sse3,ssse3,sse4,avx,avx2")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>
using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
typedef unsigned int ui;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef tuple<int, int, int> ti3;
typedef tuple<int, int, int, int> ti4;
typedef stack<int> si;
typedef queue<int> qi;
typedef priority_queue<int> pqi;
typedef pair<ll, ll> pll;
typedef vector<ll> vl;
typedef tuple<ll, ll, ll> tl3;
typedef tuple<ll, ll, ll, ll> tl4;
typedef stack<ll> sl;
typedef queue<ll> ql;
typedef priority_queue<ll> pql;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>ordered_set;
const int dx[4] = { 1,0,-1,0 };
const int dy[4] = { 0,1,0,-1 };
const int ddx[8] = { 0,0,1,1,1,-1,-1,-1 }, ddy[8] = { 1,-1,1,0,-1,1,0,-1 };
ll POW(ll a, ll b, ll MMM) { ll ret = 1; for (; b; b >>= 1, a = (a*a) % MMM)if (b & 1)ret = (ret*a) % MMM; return ret; }
ll GCD(ll a, ll b) { return b ? GCD(b, a%b) : a; }
ll LCM(ll a, ll b) { if (a == 0 || b == 0)return a + b; return a / GCD(a, b) * b; }
ll INV(ll a, ll m) {
ll m0 = m, y = 0, x = 1;
if (m == 1) return 0;
while (a > 1) {
ll q = a / m;
ll t = m;
m = a % m, a = t;
t = y;
y = x - q * y;
x = t;
}
if (x < 0) x += m0;
return x;
}
pll EXGCD(ll a, ll b) {
if (b == 0) return { 1,0 };
auto t = EXGCD(b, a%b);
return { t.second,t.first - t.second*(a / b) };
}
bool OOB(ll x, ll y, ll N, ll M) { return 0 > x || x >= N || 0 > y || y >= M; }
#define X first
#define Y second
#define rep(i,a,b) for(int i = a; i < b; i++)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define sz(a) ((int)(a.size()))
#define sf1(a) cin >> a
#define sf2(a,b) cin >> a >> b
#define sf3(a,b,c) cin >> a >> b >> c
#define sf4(a,b,c,d) cin >> a >> b >> c >> d
#define sf5(a,b,c,d,e) cin >> a >> b >> c >> d >> e
#define sf6(a,b,c,d,e,f) cin >> a >> b >> c >> d >> e >> f
#define pf1(a) cout << (a) << ' '
#define pf2(a,b) cout << (a) << ' ' << (b) << ' '
#define pf3(a,b,c) cout << (a) << ' ' << (b) << ' '<< (c) << ' '
#define pf4(a,b,c,d) cout << (a) << ' ' << (b) << ' '<< (c) << ' '<< (d) << ' '
#define pf5(a,b,c,d,e) cout << (a) << ' ' << (b) << ' '<< (c) << ' '<< (d) << ' '<< (e) << ' '
#define pf6(a,b,c,d,e,f) cout << (a) << ' ' << (b) << ' '<< (c) << ' '<< (d) << ' '<< (e) << ' ' << (f) << ' '
#define pf0l() cout << '\n';
#define pf1l(a) cout << (a) << '\n'
#define pf2l(a,b) cout << (a) << ' ' << (b) << '\n'
#define pf3l(a,b,c) cout << (a) << ' ' << (b) << ' '<< (c) << '\n'
#define pf4l(a,b,c,d) cout << (a) << ' ' << (b) << ' '<< (c) << ' '<< (d) << '\n'
#define pf5l(a,b,c,d,e) cout << (a) << ' ' << (b) << ' '<< (c) << ' '<< (d) << ' '<< (e) << '\n'
#define pf6l(a,b,c,d,e,f) cout << (a) << ' ' << (b) << ' '<< (c) << ' '<< (d) << ' '<< (e) << ' ' << (f) << '\n'
#define pfvec(V) for(auto const &t : V) pf1(t)
#define pfvecl(V) for(auto const &t : V) pf1(t); pf0l()
int n,m;
int board[1005][1005];
int vis[1005][1005];
int cnt[1000005];
int main(void) {
ios::sync_with_stdio(false);
cin.tie(0);
cout << fixed;
cout.precision(20);
///////////////////////////////////////////////
sf2(n,m);
rep(i,0,n) rep(j,0,m) sf1(board[i][j]);
int area = 0;
rep(i,0,n){
rep(j,0,m){
if(vis[i][j] or board[i][j]==0) continue;
area++;
queue<pii> Q;
Q.push({i,j});
vis[i][j] = area;
while(!Q.empty()){
auto cur = Q.front(); Q.pop();
cnt[area]++;
rep(dir,0,4){
int nx = cur.X+dx[dir];
int ny = cur.Y+dy[dir];
if(OOB(nx,ny,n,m)) continue;
if(vis[nx][ny] or board[nx][ny] == 0) continue;
Q.push({nx,ny});
vis[nx][ny] = area;
}
}
}
}
int mx = 0;
rep(i,0,n){
rep(j,0,m){
if(board[i][j] == 1) continue;
int val = 1;
vi occur;
rep(dir,0,4){
int nx = i+dx[dir];
int ny = j+dy[dir];
if(OOB(nx,ny,n,m)) continue;
if(board[nx][ny]==0) continue;
bool dup = 0;
for(auto e : occur){
if(vis[nx][ny] == e){
dup=1;
break;
}
}
if(dup) continue;
occur.pb(vis[nx][ny]);
val += cnt[vis[nx][ny]];
}
mx = max(mx,val);
}
}
pf1l(mx);
}