Submission #58869

#	Time	Username	Problem	Language	Result	Execution time	Memory
58869		Benq	Bomb (IZhO17_bomb)	C++14	41 / 100	1095 ms	132096 KiB

bomb

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

using namespace std;
using namespace __gnu_pbds;
 
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;

typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;

typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)

#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()

const int MOD = 1000000007;
const ll INF = 1e18;
const int MX = 2505;

int cum1[MX][MX], cum2[MX][MX];
char gr[MX][MX];
int n,m;

bool ok(int x, int y) {
    FOR(i,1,n+1) FOR(j,1,m+1) cum2[i][j] = 0;
    F0R(i,n+1-x) F0R(j,m+1-y) if (cum1[i+x][j+y]-cum1[i][j+y]-cum1[i+x][j]+cum1[i][j] == x*y) {
        cum2[i+1][j+1] ++;
        cum2[i+1][j+1+y] --;
        cum2[i+1+x][j+1] --;
        cum2[i+1+x][j+1+y] ++;
    }
    FOR(i,1,n+1) FOR(j,1,m+1) {
        cum2[i][j] += cum2[i][j-1]+cum2[i-1][j]-cum2[i-1][j-1];
        if (gr[i][j] == '1' && !cum2[i][j]) return 0;
    }
    return 1;
}

int main() {
    // freopen("bomb.in","r",stdin);
    // freopen("bomb.out","w",stdout);
    cin >> n >> m;
    FOR(i,1,n+1) FOR(j,1,m+1) {
        cin >> gr[i][j];
        cum1[i][j] = cum1[i-1][j]+cum1[i][j-1]-cum1[i-1][j-1];
        if (gr[i][j] == '1') cum1[i][j] ++;
    }
    int x = 0, ans = 0;
    FORd(i,1,n+1) {
        while (ok(i,x+1)) x ++;
        ans = max(ans,i*x);
    }
    cout << ans;
}

/* Look for:
* the exact constraints (multiple sets are too slow for n=10^6 :( ) 
* special cases (n=1?)
* overflow (ll vs int?)
* array bounds
*/

• Subtask 1: 41 / 100