제출 #831262

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
831262		vjudge1	Bomb (IZhO17_bomb)	C++17	100 / 100	312 ms	55992 KiB

bomb

// 赤コーダーになりたい
// お願い いいですか？

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

// Pragmas
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize("unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

// Namespaces
using namespace std;
using namespace __gnu_pbds;

// Data types
using si	= short int;
using ll	= long long;
using lll	= __int128;
using ld	= long double;

// Pairs
using pii	= pair<int, int>;
using psi	= pair<si, si>;
using pll	= pair<ll, ll>;
using plll	= pair<lll, lll>;
using pld	= pair<ld, ld>;
#define fi	first
#define se	second

// For
#define Frue(i, n, N)		for (int i = (n); i <= (N); i++)
#define  Fru(i, n, N)		for (int i = (n); i <  (N); i++)
#define Frde(i, n, N)		for (int i = (n); i >= (N); i--)
#define  Frd(i, n, N)		for (int i = (n); i >  (N); i--)

// PBDS
template<typename Z>
using ordered_set	= tree<Z, null_type, less<Z>, rb_tree_tag, tree_order_statistics_node_update>;

// Various outputs
template<typename Y, typename Z> ostream& operator<<(ostream &os, const pair<Y, Z> &p) {
	return os << '(' << p.fi << ',' << p.se << ')';
}
template<typename Z> ostream& operator<<(ostream &os, const vector<Z> &v) {
	os << '{'; bool _first = 1;
	for (auto &i : v) {if (!_first) os << ", "; os << i; _first = 0;}
	return os << '}';
}
template<typename Z, unsigned long long sz> ostream& operator<<(ostream &os, const array<Z, sz> &arr) {
	os << '{'; bool _first = 1;
	for (auto &i : arr) {if (!_first) os << ", "; os << i; _first = 0;}
	return os << '}';
}

// Quick macro functions
#define sqr(x)			((x)*(x))
#define debug(x)		cout << #x << " = " << (x) << '\n'
#define debugV(v, x)	cout << #v << "[" << (x) << "] = " << (v[x]) << '\n'
#define rrebug(x)		cerr << #x << " = " << (x) << '\n'
#define rrebugV(v, x)	cerr << #v << "[" << (x) << "] = " << (v[x]) << '\n'

#define All(x)			x.begin(), x.end()
#define Sort(x)			sort(All(x))
#define Reverse(x)		reverse(All(x))
#define Uniqueify(x)	Sort(x); x.erase(unique(All(x)), x.end())

#define RandomSeed			chrono::steady_clock::now().time_since_epoch().count()
#define MultipleTestcases	int _tc; cin >> _tc; for (int _cur_tc = 1; _cur_tc <= _tc; _cur_tc++)

// Check min and max
template<typename Z> void chmin(Z &a, Z b) {a = min(a, b);}
template<typename Z> void chmax(Z &a, Z b) {a = max(a, b);}
 
// Modular arithmetic
template<int MOD>
class ModInt {
  public:
	int v;
	ModInt() : v(0) {}
	ModInt(long long _v) {
		v = int((-MOD < _v && _v < MOD) ? (_v) : (_v % MOD));
		if (v < 0) v += MOD;
	}
 
	friend bool operator==(const ModInt &a, const ModInt &b) {return a.v == b.v;}
	friend bool operator!=(const ModInt &a, const ModInt &b) {return a.v != b.v;}
	friend bool operator< (const ModInt &a, const ModInt &b) {return a.v <  b.v;}
	friend bool operator<=(const ModInt &a, const ModInt &b) {return a.v <= b.v;}
	friend bool operator> (const ModInt &a, const ModInt &b) {return a.v >  b.v;}
	friend bool operator>=(const ModInt &a, const ModInt &b) {return a.v >= b.v;}
 
	ModInt &operator+=(const ModInt &a) {if ((v += a.v) >= MOD) v -= MOD; return *this;}
	ModInt &operator-=(const ModInt &a) {if ((v -= a.v) < 0) v += MOD; return *this;}
	ModInt &operator*=(const ModInt &a) {v = 1ll * v * a.v % MOD; return *this;}
	ModInt &operator/=(const ModInt &a) {return (*this) *= inverse(a);}
 
	friend ModInt pow(ModInt a, long long x) {
		ModInt res = 1;
		for (; x; x /= 2, a *= a) if (x & 1) res *= a;
		return res;
	}
	friend ModInt inverse(ModInt a) {return pow(a, MOD - 2);}
 
	ModInt operator+ () const {return ModInt( v);}
	ModInt operator- () const {return ModInt(-v);}
	ModInt operator++() const {return *this += 1;}
	ModInt operator--() const {return *this -= 1;}
 
	friend ModInt operator+(ModInt a, const ModInt &b) {return a += b;}
	friend ModInt operator-(ModInt a, const ModInt &b) {return a -= b;}
	friend ModInt operator*(ModInt a, const ModInt &b) {return a *= b;}
	friend ModInt operator/(ModInt a, const ModInt &b) {return a /= b;}
 
	friend istream &operator>>(istream &is, ModInt &v) {return is >> v.v;}
	friend ostream &operator<<(ostream &os, const ModInt &v) {return os << v.v;}
};
const int ModA	= 998244353;
const int ModC	= 1e9 + 7;
using MintA	= ModInt<ModA>;
using MintC	= ModInt<ModC>;

// Other constants
const ll INF	= 1e18;
const ll iINF	= 1e9;
const ld EPS	= 1e-9;
const ld iEPS	= 1e-6;

const int maxN	= 2523;

int N, M;
char grid[maxN][maxN];
int up[maxN][maxN], dn[maxN][maxN], minH[maxN];
int boundH = iINF, boundW = iINF, ans = 0;

int main() {
	ios_base::sync_with_stdio(false); cin.tie(NULL);

	cin >> N >> M;
	for (int i = 1; i <= N; i++) {
		for (int j = 1; j <= M; j++) {
			cin >> grid[i][j];
		}
	}

	// Precompute up, dn, and boundH
	for (int j = 1; j <= M; j++) {
		for (int i = 1; i <= N; i++) {
			if (grid[i][j] == '0') {
				up[i][j] = 0;
			} else {
				up[i][j] = up[i-1][j] + 1;
				if ((i == N) || (grid[i+1][j] == '0')) {
					boundH = min(boundH, up[i][j]);
				}
			}
		}

		for (int i = N; i >= 1; i--) {
			if (grid[i][j] == '0') {
				dn[i][j] = 0;
			} else {
				dn[i][j] = dn[i+1][j] + 1;
			}
		}
	}

	// Precompute boundW
	for (int i = 1; i <= N; i++) {
		int span = 0;
		for (int j = 1; j <= M; j++) {
			if (grid[i][j] == '0') {
				span = 0;
			} else {
				span += 1;
				if ((j == M) || (grid[i][j+1] == '0')) {
					boundW = min(boundW, span);
				}
			}
		}
	}

	// Compute minH for each horizontal prefix and suffix
	for (int j = 1; j <= M; j++) {
		minH[j] = boundH;
	}
	for (int i = 1; i <= N; i++) {
		int span = 0, mnUp = iINF, mnDn = iINF;
		for (int j = 1; j <= M; j++) {
			if (grid[i][j] == '0') {
				span = 0, mnUp = iINF, mnDn = iINF;
			} else {
				span += 1;
				mnUp = min(mnUp, up[i][j]);
				mnDn = min(mnDn, dn[i][j]);

				minH[span] = min(minH[span], mnUp + mnDn - 1);
			}
		}
		
		span = 0, mnUp = iINF, mnDn = iINF;
		for (int j = M; j >= 1; j--) {
			if (grid[i][j] == '0') {
				span = 0, mnUp = iINF, mnDn = iINF;
			} else {
				span += 1;
				mnUp = min(mnUp, up[i][j]);
				mnDn = min(mnDn, dn[i][j]);

				minH[span] = min(minH[span], mnUp + mnDn - 1);
			}
		}
	}

	for (int j = 1; j <= boundW; j++) {
		ans = max(ans, minH[j] * j);
	}

	cout << ans << '\n';
}

• Subtask 1: 100 / 100