Submission #892895

#	Time	Username	Problem	Language	Result	Execution time	Memory
892895		Trisanu_Das	Catfish Farm (IOI22_fish)	C++17	100 / 100	250 ms	25224 KiB

fish

#include "fish.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
 
vector<pair<int, int> > fishes[100005];
 
struct SegmentTree{
    ll tree[1 << 18];
    void init() {
        memset(tree, 0xcf, sizeof(tree));
    }
    void upd(int idx, int s, int e, int l, int r, ll val) {
        if (e < l || r < s) return;
        if (l <= s && e <= r) {
            tree[idx] = max(tree[idx], val);
            return;
        }
        int mid = (s + e) / 2;
        upd(2 * idx, s, mid, l, r, val);
        upd(2 * idx + 1, mid + 1, e, l, r, val);
    }
    ll qry(int idx, int s, int e, int x) {
        if (s == e) return tree[idx];
        int mid = (s + e) / 2;
        if (x <= mid) return max(tree[idx], qry(2 * idx, s, mid, x));
        return max(tree[idx], qry(2 * idx + 1, mid + 1, e, x));
    }
} st_up, st_down;
 
ll max_weights(int N, int M, vector<int> X, vector<int> Y, vector<int> W) {
    for (int i = 0; i < M; i++) fishes[X[i] + 1].push_back({Y[i] + 1, W[i]});
    ll till_now = 0;
    st_down.init();
    for (int i = 1; i <= N; i++) {
        sort(fishes[i].begin(), fishes[i].end());
        for (auto [j, w] : fishes[i])  st_up.upd(1, 0, N + 1, j + 1, N + 1, st_up.qry(1, 0, N + 1, j) + w);
        reverse(fishes[i].begin(), fishes[i].end());
        for (auto [j, w] : fishes[i]) st_down.upd(1, 0, N + 1, 0, j - 1, st_down.qry(1, 0, N + 1, j) + w);
        ll u_res = st_up.qry(1, 0, N + 1, N + 1), d_res = st_down.qry(1, 0, N + 1, 0);
        st_up.upd(1, 0, N + 1, 0, N + 1, d_res);
        st_down.upd(1, 0, N + 1, 0, N + 1, till_now);
        till_now = max(u_res, d_res);
    }
    return st_down.qry(1, 0, N + 1, 0);
}

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