| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 1209317 | SpyrosAliv | Nafta (COI15_nafta) | C++20 | 0 ms | 0 KiB |
#include <bits/stdc++.h>
using namespace std;
#define int long long
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>> ranges;
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);
ranges.push_back({lb, rb, s});
}
}
swap(n, m);
for (auto [l, r, s]: ranges) {
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";
}
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int t = 1;
while (t--) solve();
return 0;
}