Submission #1301217

#	Time	Username	Problem	Language	Result	Execution time	Memory
1301217		i_elhdad	Feast (NOI19_feast)	C++20	100 / 100	580 ms	35556 KiB

feast

//    #pragma GCC optimize ("O3")
//    #pragma GCC optimize ("unroll-loops")
//    #pragma comment(linker, "/STACK:2000000")
#include<bits/stdc++.h>

using namespace std;
#define ll long long
#define int ll
#define ld long double
#define  ui unsigned int
#define endl "\n"
#define FOCUS ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);

void Go() {
    ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
}

const int N = 3e5 + 5;
pair<ll,ll> dp[N][2];
vector<int> vals(N);
ll C = 0;
int n, k;

pair<ll,ll> merge(pair<ll,ll> a, pair<ll,ll> b) {
    if (a.first>b.first)return a;
    if (b.first>a.first)return b;
    if (a.second<b.second)return a;
    return b;
}

pair<ll,ll> solve(int idx,int open) {
    if (idx == n) {
        return {0, 0};
    }
    auto &ret = dp[idx][open];
    if (ret.first != -1)return ret;
    ret = {0, 0};
    if (!open) {
        auto res = solve(idx + 1, open);
        ret = merge(ret, res);
    }
    if (!open) {
        auto res = solve(idx + 1, 1);
        res.first += -C + vals[idx];
        res.second++;
        ret = merge(res, ret);
    }
    if (open) {
        // close
        auto res = solve(idx, 0);
        ret = merge(res, ret);
        // contine
    }
    if (open) {
        auto res = solve(idx + 1, 1);
        res.first += vals[idx];
        ret = merge(res, ret);
    }
    return ret;
}

signed main() {
    // Go();
    FOCUS
    cin >> n >> k;
    for (int i = 0; i < n; i++)cin >> vals[i];
    int lo = 0, hi = 1e13;
    pair<ll,ll> best;
    ll Pen = 0;
    for (int i = 0; i < N; i++) {
        for (int j = 0; j < 2; j++) {
            dp[i][j] = {-1, -1};
        }
    }
    C = 0;
    while (lo <= hi) {
        auto mid = (lo + hi) / 2;
        for (int i = 0; i < N; i++) {
            for (int j = 0; j < 2; j++) {
                dp[i][j] = {-1, -1};
            }
        }
        C = mid;
        auto res = solve(0, 0);
        if (res.second > k) {
            lo = mid + 1;
        } else {
            best = res;
            Pen = C;
            hi = mid - 1;
        }
    }
    cout << best.first + k * Pen;
    // open close
    // skip
    // binary search on extra cost to add person
}

Compilation message (stderr)

feast.cpp: In function 'void Go()':
feast.cpp:17:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   17 |     freopen("input.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
feast.cpp:18:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   18 |     freopen("output.txt", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 8 / 8
• Subtask 3: 18 / 18
• Subtask 4: 10 / 10
• Subtask 5: 11 / 11
• Subtask 6: 20 / 20
• Subtask 7: 29 / 29