Submission #667032

#	Time	Username	Problem	Language	Result	Execution time	Memory
667032		tatyam	Catfish Farm (IOI22_fish)	C++17	100 / 100	260 ms	23208 KiB

fish

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
void chmax(ll& a, ll b){ if(a < b) a = b; }

// range chmax・1 点取得 で O(M log N)
struct SegTree {
    ll n;
    vector<ll> seg;
    SegTree(ll n): n(n), seg(n * 2) {}
    void range_chmax(ll l, ll r, ll x) {
        l += n;
        r += n;
        while(l < r){
            if(l & 1) chmax(seg[l++], x);
            if(r & 1) chmax(seg[--r], x);
            l >>= 1; r >>= 1;
        }
    }
    ll operator[](ll i) const {
        i += n;
        ll x = 0;
        do chmax(x, seg[i]); while(i >>= 1);
        return x;
    }
};
ll max_weights(int N, int M, vector<int> X, vector<int> Y, vector<int> W) {
    vector fish(N, vector<pair<ll, ll>>{});
    for (ll i = 0; i < M; i++) {
        fish[X[i]].emplace_back(Y[i], W[i]);
    }
    for (auto& v : fish) sort(v.begin(), v.end());
    SegTree up(N + 1), down(N + 1);
    ll zero = 0;
    for(ll x = 0; x + 1 < N; x++) {
        for(auto [y, w] : fish[x]) {
            up.range_chmax(y + 1, N + 1, up[y] + w);
        }
        reverse(fish[x + 1].begin(), fish[x + 1].end());
        for(auto [y, w] : fish[x + 1]) {
            down.range_chmax(0, y + 1, down[y + 1] + w);
        }
        reverse(fish[x + 1].begin(), fish[x + 1].end());
        const ll zero_ = exchange(zero, down[0]);
        down.range_chmax(0, N + 1, max(up[N], zero_));
        up.range_chmax(0, N + 1, zero_);
    }
    return max({zero, down[0], up[N]});
}

• 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