Submission #1129141

#	Time	Username	Problem	Language	Result	Execution time	Memory
1129141		Gray	Bomb (IZhO17_bomb)	C++17	34 / 100	503 ms	147604 KiB

bomb

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ull unsigned long long
#define ld long double
#define ff first
#define ss second
#define ln "\n"
#define mp make_pair

const ll INF = 2e18;
const ll MOD = 1e9+7;

void solve(){
    ll n, m; cin >> n >> m;
    vector<vector<ll>> a(n+1, vector<ll>(m+1));
    for (ll i=1; i<=n; i++){
        for (ll j=1; j<=m; j++){
            char x; cin >> x; a[i][j]=x-'0';
        }
    }
    vector<vector<ll>> wl(n+1, vector<ll>(m+1)), wr(n+1, vector<ll>(m+1));
    for (ll i=1; i<=n; i++){
        for (ll j=1; j<=m; j++){
            if (a[i][j]) wl[i][j]=wl[i][j-1]+1;
        }
        for (ll j=m; j>=1; j--){
            if (a[i][j]) wr[i][j]=1;
            if (j+1<=m) wr[i][j]+=wr[i][j+1];
        }
    }
    vector<ll> h(n+1, INF), ah(n+1);
    for (ll j=1; j<=m; j++){
        ll exist=0;
        for (ll i=1; i<=n; i++){
            if (a[i][j]) exist=1;
        }
        if (!exist) continue;
        ll l=INF, r=INF, hcnt=0;
        ah.assign(n+1, INF);
        for (ll i=1; i<=n; i++){
            if (a[i][j]){
                l=min(l, wl[i][j]); r=min(r, wr[i][j]);
                hcnt++;
                ah[hcnt]=min(ah[hcnt], l+r-1);
                // cout << i << "-" << j << ": " << hcnt << "-" << l+r-1 << ln;
            }else{
                l=INF; r=INF; hcnt=0;
            }
        }
        l=INF; r=INF; hcnt=0;
        for (ll i=n; i>=1; i--){
            if (a[i][j]){
                l=min(l, wl[i][j]); r=min(r, wr[i][j]);
                hcnt++; ah[hcnt]=min(ah[hcnt], l+r-1);
            }else{
                l=INF; r=INF; hcnt=0;
            }
        }
        for (ll i=1; i<=n; i++){
            h[i]=min(h[i], (ah[i]==INF?0:ah[i]));
        }
    }
    ll res=0;
    for (ll i=1; i<=n; i++){
        if (h[i]==INF) continue;
        res=max(res, i*h[i]);
    }
    cout << res << ln;
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    auto start = chrono::high_resolution_clock::now();
    ll t=1;
    // cin >> t;
    while (t--) solve();
    #ifdef LOCAL
    auto duration = chrono::duration_cast<chrono::microseconds>(chrono::high_resolution_clock::now() - start);
    cout << setprecision(0) << fixed << "time: " << (double)duration.count()/1000.0 << " milliseconds" << endl;
    #endif
}

• Subtask 1: 34 / 100