Submission #1072316

#	Time	Username	Problem	Language	Result	Execution time	Memory
1072316		vjudge1	Catfish Farm (IOI22_fish)	C++17	0 / 100	1040 ms	8384 KiB

fish

#include "fish.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vll = vector <ll>;
using ii = pair <ll, ll>;
using vii = vector <ii>;
using vi = vector <int>;

// dp[i][j] = max grams caught if last pier in column <= i-1 and also\
caught the first j catfish from column i

// pier worth extending up to every catfish or until the end (O(n+m) optimal maximal piers)

const ll MAXN = 3E3+16, INF = ll(1E18)+16;
ll dp[MAXN][MAXN];
vii ccs[MAXN];
// vll ps[MAXN];
ll max_weights (int n, int m, vi vx, vi vy, vi vw) {
    for (ll i = 0; i < m; i++)
        ccs[vx[i]].push_back({ vy[i], vw[i] });
    for (ll x = 0; x < n; x++) {
        sort(ccs[x].begin(), ccs[x].end());
        ccs[x].insert(ccs[x].begin(), ii{ -1, 0 });
        // ps[x].push_back(0);
        ll acc = 0;
        for (auto &[y, w] : ccs[x]) {
            acc += w;
            w = acc;
        }
    }
    auto fget = [&](ll x, ll y) -> ll { // pier at column x up until y
        // ll ans = 0;
        if (x < 0 || n <= x) return 0;
        return (upper_bound(ccs[x].begin(), ccs[x].end(), ii{ y-1, INF })-1)->second;
        // if ()
    };
    auto ffix = [&](ll x1, ll y1, ll x2, ll y2) -> ll { // fix the combination of those dps
        assert(x1 < x2);
        if (x1+2 < x2) return 0;
        if (x1+2 == x2) {
            return fget(x1+1, min(y1, y2));
        }
        if (x1+1 == x2) {
            return fget(x1, y2) + fget(x2, y1);
        }
        assert(false);
    };
    ll ans = 0;
    for (ll x = 0; x < n; x++) {
        for (ll y = 0; y <= n; y++) {
            ll ra = fget(x-1, y) + fget(x+1, y);
            dp[x][y] = ra;
            for (ll x2 = max(0LL, x-3); x2 < x; x2++) {
                for (ll y2 = 0; y2 <= n; y2++) {
                    dp[x][y] = max(dp[x][y], dp[x2][y2] + ra - ffix(x2, y2, x, y));
                }
            }
            // cerr << dp[x][y] << ' ';
            ans = max(ans, dp[x][y]);
        }
        // cerr << '\n';
    }
    return ans;
}

Compilation message (stderr)

fish.cpp:10:1: warning: multi-line comment [-Wcomment]
   10 | // dp[i][j] = max grams caught if last pier in column <= i-1 and also\
      | ^

• Subtask 1: 0 / 3
• Subtask 2: 0 / 6
• Subtask 3: 0 / 9
• Subtask 4: 0 / 14
• Subtask 5: 0 / 21
• Subtask 6: 0 / 17
• Subtask 7: 0 / 14
• Subtask 8: 0 / 16