Submission #981754

#	Time	Username	Problem	Language	Result	Execution time	Memory
981754		12345678	Nafta (COI15_nafta)	C++17	100 / 100	416 ms	114304 KiB

nafta

#include <bits/stdc++.h>

using namespace std;

const int nx=2005;

int n, m, mp[nx][nx], dp[nx][nx], mn[nx][nx], cnt[nx][nx], g[nx][nx], t, s[nx][nx],vs[nx][nx], dx[4]={0, 0, 1, -1}, dy[4]={1, -1, 0, 0}, ans[nx];
char ch;
queue<pair<int, int>> q;

void solve(int l, int r, int optl, int optr, int layer)
{
    if (r<l) return;
    int md=(l+r)/2;
    pair<int, int> mx={INT_MIN, -1};
    for (int i=optl; i<=min(md-1, optr); i++) mx=max(mx, {dp[layer-1][i]+cnt[md][i], i});
    dp[layer][md]=mx.first;
    solve(l, md-1, optl, mx.second, layer);
    solve(md+1, r, mx.second, optr, layer);
}

int main()
{
    cin.tie(NULL)->sync_with_stdio(false);
    cin>>n>>m;
    for (int i=1; i<=n; i++) for (int j=1; j<=m; j++) cin>>ch, mp[i][j]=(ch=='.')?-1:ch-'0';
    for (int i=1; i<=n; i++)
    {
        for (int j=1; j<=m; j++)
        {
            if (vs[i][j]||mp[i][j]==-1) continue;
            q.push({i, j});
            vs[i][j]=1;
            int k=INT_MAX, sm=0;
            vector<pair<int, int>> v;
            while (!q.empty())
            {
                v.push_back(q.front());
                auto [x, y]=q.front();
                q.pop();
                k=min(k, y);
                sm+=mp[x][y];
                for (int d=0; d<4; d++)
                {
                    int nwx=x+dx[d], nwy=y+dy[d];
                    if (nwx<1||nwx>n||nwy<1||nwy>m||mp[nwx][nwy]==-1||vs[nwx][nwy]) continue;
                    q.push({nwx, nwy});
                    vs[nwx][nwy]=1;
                }
            }
            ++t;
            for (auto [x, y]:v) g[x][y]=t, mn[x][y]=k, s[x][y]=sm; //cout<<"group "<<t<<' '<<x<<' '<<y<<'\n';
        }
    }
    for (int i=1; i<=m; i++)
    {
        set<int> mem;
        for (int j=1; j<=n; j++)
        {
            if (mp[j][i]==-1||mem.find(g[j][i])!=mem.end()) continue;
            mem.insert(g[j][i]);
            cnt[i][mn[j][i]-1]+=s[j][i];
        }
        for (int j=i; j>=0; j--) cnt[i][j]+=cnt[i][j+1]; //cout<<"debug "<<i<<' '<<j<<' '<<cnt[i][j]<<'\n';
    }
    for (int i=1; i<=m; i++) solve(1, m, 0, m, i);
    for (int i=1; i<=m; i++) for (int j=1; j<=m; j++) ans[i]=max(ans[i], dp[i][j]);
    for (int i=1; i<=m; i++) cout<<ans[i]<<'\n';
}

• Subtask 1: 11 / 11
• Subtask 2: 23 / 23
• Subtask 3: 66 / 66