Submission #1268568

#	Time	Username	Problem	Language	Result	Execution time	Memory
1268568		monaxia	Feast (NOI19_feast)	C++20	59 / 100	114 ms	23660 KiB

feast

#include <bits/stdc++.h>
#include <ext/random>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>

// #pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#define pb push_back
#define ppb pop_back
#define fr first
#define sc second
#define all(v) v.begin(), v.end()
#define vektor vector

using namespace std;
using namespace __gnu_pbds; 

using ll = long long;
using ull = unsigned long long;
using ld = long double;

constexpr ull Mod = 1e9 + 7;
constexpr ull sqr = 547;
constexpr ld eps = 1e-9;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll random(ll l, ll r) {if(l <= r) return uniform_int_distribution <ll> (l, r)(rng); return -1;} 

void solve(){ 
    ll n, k;
    cin >> n >> k;

    vector <ll> a(n + 1);
    vector <vector <pair <ll, ll>>> dp(n + 1, vector <pair <ll, ll>> (2));

    for(int i = 1; i <= n; i ++) cin >> a[i];

    ll l = 0, r = 1e9 * n, ans = 1e9 * n;

    while(l <= r){
        ll mid = (l + r) >> 1;

        dp[1][0] = {0, 0};
        dp[1][1] = {a[1] - mid, 1};

        for(int i = 2; i <= n; i ++){
            dp[i][0] = max(dp[i - 1][0], dp[i - 1][1]);
            dp[i][1] = max({make_pair(dp[i - 1][0].fr + a[i] - mid, dp[i - 1][0].sc + 1), make_pair(dp[i - 1][1].fr + a[i], dp[i - 1][1].sc), make_pair(dp[i - 1][1].fr + a[i] - mid, dp[i - 1][1].sc + 1)});
            dp[i][1] = max(dp[i][1], {a[i] - mid, 1});
        }

        if(max(dp[n][0], dp[n][1]).sc > k) l = mid + 1;
        else r = mid - 1, ans = mid;

        // cout << max(dp[n][0], dp[n][1]).sc << " " << mid << " " << ans << "\n";
    }

    dp[1][0] = {0, 0};
    dp[1][1] = {a[1] - ans, 1};

    for(int i = 2; i <= n; i ++){
        dp[i][0] = max(dp[i - 1][0], dp[i - 1][1]);
        dp[i][1] = max({make_pair(dp[i - 1][0].fr + a[i] - ans, dp[i - 1][0].sc + 1), make_pair(dp[i - 1][1].fr + a[i], dp[i - 1][1].sc), make_pair(dp[i - 1][1].fr + a[i] - ans, dp[i - 1][1].sc + 1)});
        dp[i][1] = max(dp[i][1], {a[i] - ans, 1});
    }

    cout << max(dp[n][0], dp[n][1]).fr + ans * k;
} 

main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL); 

    if(fopen("COUNTSEQ.inp", "r")){
        freopen("COUNTSEQ.inp", "r", stdin);
        freopen("COUNTSEQ.out", "w", stdout);
    }

    int t = 1;

    // cin >> t;

    while(t --){
        solve();
        cout << "\n";
    }
}

Compilation message (stderr)

feast.cpp:72:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   72 | main(){
      | ^~~~
feast.cpp: In function 'int main()':
feast.cpp:77:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |         freopen("COUNTSEQ.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
feast.cpp:78:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   78 |         freopen("COUNTSEQ.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 4
• Subtask 2: 0 / 8
• Subtask 3: 18 / 18
• Subtask 4: 10 / 10
• Subtask 5: 11 / 11
• Subtask 6: 20 / 20
• Subtask 7: 0 / 29