Submission #1106873

#	Time	Username	Problem	Language	Result	Execution time	Memory
1106873		InvMOD	Split the sequence (APIO14_sequence)	C++14	50 / 100	2059 ms	4148 KiB

sequence

#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second
#define gcd __gcd
#define sz(v) (int) v.size()
#define pb push_back
#define pi pair<int,int>
#define all(v) (v).begin(), (v).end()
#define compact(v) (v).erase(unique(all(v)), (v).end())
#define FOR(i, a, b) for(int i = (a); i <= (b); i++)
#define dbg(x) "[" #x " = " << (x) << "]"
///#define int long long

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

template<typename T> bool ckmx(T& a, const T& b){if(a <= b) return a = b, true; return false;}
template<typename T> bool ckmn(T& a, const T& b){if(a >= b) return a = b, true; return false;}

const int N = 1e5+5;
const int K = 2e2+5;
const ll INF = 1e18;


ll n, k, a[N], pref[N], dp[K][N];

namespace Brute{
    const int N = 1e3+5;

    ll dp[K][N], trace[K][N];

    void process()
    {
        for(int i = 1; i <= n; i++){
            dp[0][i] = 0;

            for(int j = 1; j <= k; j++){
                for(int x = j+1; x <= i; x++){
                    if(ckmx(dp[j][i], dp[j-1][x-1] + (pref[i] - pref[x-1]) * pref[x-1])){
                        trace[j][i] = x;
                    }
                }
            }
        }
        cout << dp[k][n] <<"\n";

        vector<int> path;

        for(int cur_k = k, cur_pos = n; cur_k; cur_pos = trace[cur_k][cur_pos]-1, --cur_k){
            path.push_back(trace[cur_k][cur_pos]-1);
        }

        reverse(all(path));
        for(int i = 0; i < sz(path); i++) cout << path[i] <<" "; cout <<"\n";
        return;
    }
}

struct Line{
    ld a,b;
    Line(ld a = 0, ld b = 0): a(a), b(b) {}

    ld intersect(Line& x){return (x.b - b)/(a - x.a);}
    bool operator < (const Line& x) const{return a < x.a;}
};

struct CHT{
    deque<pair<Line,ld>> dq;

    void ins(Line x){
        while(!dq.empty() && dq.back().second >= dq.back().first.intersect(x)) dq.pop_back();

        if(dq.empty()){
            dq.push_back(make_pair(x, -INF));
        }
        else dq.push_back(make_pair(x, dq.back().first.intersect(x)));
    }

    Line get(ll x){
        while(dq.size() > 1 && dq[1].second <= x) dq.pop_front();

        dq.front().second = -INF;
        return dq.front().first;
    }
};

void solve()
{
    cin >> n >> k;
    for(int i = 1; i <= n; i++){
        cin >> a[i];
        pref[i] = a[i] + pref[i-1];
    }

    Brute::process();
}

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    #define name "InvMOD"
    if(fopen(name".INP", "r")){
        freopen(name".INP","r",stdin);
        freopen(name".OUT","w",stdout);
    }

    int t = 1; //cin >> t;
    while(t--) solve();
    return 0;
}

Compilation message (stderr)

sequence.cpp: In function 'void Brute::process()':
sequence.cpp:57:9: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   57 |         for(int i = 0; i < sz(path); i++) cout << path[i] <<" "; cout <<"\n";
      |         ^~~
sequence.cpp:57:66: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   57 |         for(int i = 0; i < sz(path); i++) cout << path[i] <<" "; cout <<"\n";
      |                                                                  ^~~~
sequence.cpp: In function 'int main()':
sequence.cpp:109:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  109 |         freopen(name".INP","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
sequence.cpp:110:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  110 |         freopen(name".OUT","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 11 / 11
• Subtask 3: 11 / 11
• Subtask 4: 17 / 17
• Subtask 5: 0 / 21
• Subtask 6: 0 / 29