Submission #760968

#	Time	Username	Problem	Language	Result	Execution time	Memory
760968		drdilyor	Catfish Farm (IOI22_fish)	C++17	14 / 100	680 ms	2097152 KiB

fish

#include <bits/stdc++.h>
#include "fish.h"
using namespace std;
using ll = long long;

ll max_weights(
    int n, int m, vector<int> x, vector<int> y, vector<int> w) {
    vector arr(n+1, vector<pair<int,ll>>());
    for (int i = 0; i < m; i++) {
        arr[x[i]+1].emplace_back(y[i], w[i]);
    }
    for (int i = 0; i < n; i++)
        sort(arr[i].begin(), arr[i].end());
    auto pref = arr;
    for (int i = 0; i <= n; i++) {
        for (int j = 1; j < pref[i].size(); j++) {
            pref[i][j].second += pref[i][j-1].second;
        }
    }

    auto sum_right = [&](int c, int right)->ll{
        int l = -1, r = pref[c].size();
        while (l < r-1) {
            int mid = (l+r) / 2;
            if (pref[c][mid].first <= right) l = mid;
            else r= mid;
        }
        return l==-1 ? 0 : pref[c][l].second;
    };

    auto sum = [&](int c, int l, int r) { // [l, r]
        if (l <= r) return sum_right(c, r) - sum_right(c, l-1);
        else return 0ll;
    };
    vector<vector<int>> byx(n+2), used(n+1);
    for (int i = 0; i < m; i++)
        byx[x[i]+1].push_back(y[i]);
    for (int i = 0; i <= n; i++) {
        sort(byx[i].begin(), byx[i].end());
        byx[i].erase(unique(byx[i].begin(), byx[i].end()), byx[i].end());
    }
    used[0] = {0};
    for (int i = 1; i <= n; i++) {
        merge(byx[i-1].begin(), byx[i-1].end(),
                byx[i+1].begin(), byx[i+1].end(),
                back_inserter(used[i]));
        for (int& j : used[i])
            j++;
        used[i].insert(used[i].begin(), 0);
    }

    vector memo(2, vector(n+1, vector(n+1, -1ll)));
    auto dp = [&](auto& dp, bool inc, int c, int h2)->ll{
        if (c == n+1) return 0;
        int h2_key = lower_bound(used[c-1].begin(), used[c-1].end(), h2) - used[c-1].begin();
        ll& res = memo[inc][c][h2_key];
        if (res!=-1) return res;
        res = 0;
        if (inc) {
            for (int h3 : used[c]) {
                if (h3 < h2) continue;
                ll val = sum(c-1, h2, h3-1);
                res = max(res, val + dp(dp, true, c+1, h3));
                res = max(res, val + dp(dp, false, c+1, h3));
            }
        } else {
            for (int h3 : used[c]) {
                if (h3 > h2) break;
                ll val = sum(c, h3, h2-1);
                res = max(res, val + dp(dp, false, c+1, h3));
            }
        }
        res = max(res, dp(dp, true, c+1, 0));
        return res;
    };
    ll res = dp(dp, true, 1, 0);
    return res;

}

Compilation message (stderr)

fish.cpp: In function 'll max_weights(int, int, std::vector<int>, std::vector<int>, std::vector<int>)':
fish.cpp:16:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   16 |         for (int j = 1; j < pref[i].size(); j++) {
      |                         ~~^~~~~~~~~~~~~~~~

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