Submission #1209320

#	Time	Username	Problem	Language	Result	Execution time	Memory
1209320		SpyrosAliv	Nafta (COI15_nafta)	C++20	0 / 100	1 ms	1088 KiB

nafta

#include <bits/stdc++.h>
using namespace std;

vector<pair<int, int>> delta = {{-1, 0}, {1, 0}, {0, 1}, {0, -1}};
const int MN = 2005;
int grid[MN][MN], c[MN][MN], dp[MN][MN], n, m, lb, rb, s;
bool vis[MN][MN];
vector<tuple<int, int, int>> rr;

bool inside(int i, int j) {
    return i >= 1 && i <= n && j >= 1 && j <= m;
}

void flood(int i, int j) {
    s += grid[i][j];
    vis[i][j] = true;
    lb = min(lb, j);
    rb = max(rb, j);
    for (auto [pi, pj]: delta) {
        int ni = i + pi;
        int nj = j + pj;
        if (inside(ni, nj) && grid[ni][nj] != -1 && !vis[ni][nj]) {
            flood(ni, nj);
        }
    }
}

void dnc(int l, int r, int optl, int optr, int k) {
    if (l > r) return;
    int mid = (l + r) / 2;
    int best = -1, opt = -1;
    for (int i = optl; i <= min(optr, mid); i++) {
        int ans = c[i][mid];
        if (i > 1) ans += dp[i-1][k-1];
        if (ans > best) {
            best = ans;
            opt = i;
        }
    }   
    dp[mid][k] = best;
    dnc(l, mid - 1, optl, opt, k);
    dnc(mid+1, r, opt, optr, k);
}

void solve() {
    cin >> n >> m;
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            char c; cin >> c;
            if (c == '.') {
                grid[i][j] = -1;
            }
            else grid[i][j] = (c - '0');
        }
    }
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            if (vis[i][j] || grid[i][j] == -1) continue;
            s = 0;
            lb = m;
            rb = 0;
            flood(i, j);
            rr.push_back({lb, rb, s});
        }
    }
    swap(n, m);
    for (auto [l, r, s]: rr) {
        for (int i = 1; i <= n; i++) {
            if (i > l || r < i) break;
            c[i][l] += s;
            c[i][r+1] -= s;
        }
    }
    for (int i = 1; i <= n; i++) {
        for (int j = i+1; j <= n; j++) {
            c[i][j] += c[i][j-1];
        }
    }
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= i; j++) {
            dp[i][1] = max(dp[i][1], c[1][j]);
        }
    }
    for (int k = 2; k <= n; k++) {
        dnc(1, n, 1, n, k);
    }
    for (int i = 1; i <= n; i++) {
        cout << dp[n][i] << "\n";
    }
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t = 1;
    while (t--) solve();
    return 0;
}

• Subtask 1: 0 / 11
• Subtask 2: 0 / 23
• Subtask 3: 0 / 66