Submission #891437

#	Time	Username	Problem	Language	Result	Execution time	Memory
891437		nasam	Split the sequence (APIO14_sequence)	C++17	11 / 100	247 ms	46868 KiB

sequence

/*************************************
*       author: Pham Huy Khanh       *
*************************************/
#include <bits/stdc++.h>
#define ll long long
#define FOR(i,a,b) for (int i = (a), _b = (b); i <= _b; i++)
#define FOD(i,b,a) for (int i = (b), _a = (a); i >= _a; i--)
#define FORE(i, v) for (__typeof((v).begin()) i = (v).begin(); i != (v).end(); i++)
#define ALL(v) (v).begin(), (v).end()
#define BIT(x, i) (((x) >> (i)) & 1)
#define MASK(i) (1LL << (i))
#define CNTBIT(x) __builtin_popcountll(x)
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define left ___left
#define right ___right
#define pii pair<int, int>
#define DEBUG(n, a) FOR (i, 1, n) cout << a[i] << ' '; cout << endl;
#define endl "\n"
#define NAME "main"

using namespace std;

template<class X, class Y> bool maximize(X &x, Y y){ if (x < y){ x = y; return true; } return false; }
template<class X, class Y> bool minimize(X &x, Y y){ if (x > y){ x = y; return true; } return false; }

#define  gogobruhbruh  ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
#define  file(name)  if (fopen (name".inp", "r")) { freopen (name".inp", "r", stdin); freopen (name".out", "w", stdout); }

const int MOD = 1e9 + 7;

void add(int &a, int b){ if ((a += b) >= MOD) a -= MOD; }
void sub(int &a, int b){ if ((a -= b) < 0) a += MOD; }
int muti(int a, int b){ return (1LL * a * b) % MOD; }
int Pow(int x, int y){ int res = 1; for (; y; y >>= 1){ if (y & 1) res = muti(res, x); x = muti(x, x); } return res; }

const int MAX = 1e5 + 7;
const int K = 1e2 + 7;
const ll INF = 1e18 + 7;

int num, lim;
ll sum[MAX], dp[MAX];
int trace[MAX][K];

struct Line {
    ll a, b;
    int id;

    Line(ll _a, ll _b, int _id){
        a = _a; b = _b; id = _id;
    }

    ll ord(ll x){
        return a * x + b;
    }
};

struct CHT {
    vector<Line> env;
    int idx;

    void init(){
        env.clear();
        idx = 0;
    }

    bool bad(Line a, Line b, Line c){
        return (double) (b.b - a.b) * (a.a - c.a) >= (double) (c.b - a.b) * (a.a - b.a);
    }

    void add(Line newLine){
        while (env.size() >= 2 && bad(env[env.size() - 2], env.back(), newLine))
            env.pop_back();
        env.eb(newLine);
    }
    
    Line get(ll x){
        if (env.empty())
            return Line(-INF, 0, 0);
        int sz = env.size();
        if (idx >= sz)
            idx = sz - 1;
        while (idx + 1 < sz && env[idx + 1].ord(x) > env[idx].ord(x))
            idx++;
        return Line(env[idx].ord(x), 0, env[idx].id);
    }
} cht;

void solve(){
    cht.add(Line(0, 0, 0));
    FOR (j, 1, lim){
        FOR (i, 1, num){
            Line DP = cht.get(sum[i]);
            trace[i][j] = DP.id;
            cht.add(Line(sum[i], dp[i] - sum[i] * sum[i], i));
            dp[i] = DP.a;
        }
        cht.init();
    }
    cout << dp[num] << endl;
    for (num = trace[num][lim--]; lim >= 0; num = trace[num][lim--])
        cout << num << ' ';
}

void read(){
    cin >> num >> lim;
    FOR (i, 1, num)
        cin >> sum[i],
        sum[i] += sum[i - 1];
}

int main(){
    gogobruhbruh
    file("main");
    int test = 1;
    // cin >> test;
    while (test--)
      read(),
      solve();
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:30:61: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 | #define  file(name)  if (fopen (name".inp", "r")) { freopen (name".inp", "r", stdin); freopen (name".out", "w", stdout); }
      |                                                     ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
sequence.cpp:116:5: note: in expansion of macro 'file'
  116 |     file("main");
      |     ^~~~
sequence.cpp:30:95: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 | #define  file(name)  if (fopen (name".inp", "r")) { freopen (name".inp", "r", stdin); freopen (name".out", "w", stdout); }
      |                                                                                       ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
sequence.cpp:116:5: note: in expansion of macro 'file'
  116 |     file("main");
      |     ^~~~

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