Submission #964187

#	Time	Username	Problem	Language	Result	Execution time	Memory
964187		Mike_Vu	Split the sequence (APIO14_sequence)	C++14	71 / 100	105 ms	131072 KiB

sequence

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef double dou;
#define pii pair<int, int>
#define pb push_back
#define fi first
#define se second

//const ll mod = 1e9+7;

bool maximize(ll &x, ll y ){
    if (x < y) {x = y; return true;};
    return false;
}
bool minimize(ll &x, ll y){
    if (x > y) {x = y; return true;}
    return false;
}
//void add(ll &x, ll y ){
//    x += y;
//    if (x >= mod) x -= mod;
//}
//void sub(ll &x, ll y) {
//    x -= y;
//    if (x < 0) x += mod;
//}

ll divi(ll x, ll y ){
    if (x == 0 || y == 0) return 0;
    return x/y - ((x^y)<0&&x%y);
}

int temp;

struct Line{
    ll m, b;
    int pos;
    Line(ll slope, ll intercept, int p) {
        m = slope;
        b = intercept;
        pos = p;
    }
    ll operator () (ll x) {temp = pos; return m*x+b;}
    friend ll inter(Line a, Line b){
        return divi(b.b-a.b, a.m-b.m);
    }
};

struct CHT{
    vector<pair<Line, ll>> hull;
    void init() {
        hull.clear();
    }
    void update(Line a) {
        while (!hull.empty() && hull.back().se <= (inter(hull.back().fi, a))) {
            hull.pop_back();
        }
        if (hull.empty()) {
            hull.push_back(make_pair(a, LLONG_MAX));
            return;
        }
        hull.push_back(make_pair(a, inter(a, hull.back().fi)));
    }
    ll query(ll x) {
        int pos = 0;
        for (int k = hull.size()/2; k > 0; k >>= 1) {
            while (pos+k < (int)hull.size() && hull[pos+k].se >= x) pos += k;
        }
        return hull[pos].fi(x);
    }
} cht;

const int maxn = 1e5+3, maxk = 202;
int n, k;
ll dp[maxn][maxk], ps[maxn];
int track[maxn][maxk], a[maxn];

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> n >> k;
    ps[0] = 0;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        ps[i] = ps[i-1] + a[i];
    }
    for (int i = 1; i < n; i++) {
        dp[i][1] = (ps[n]-ps[i])*(ps[i]);
    }
    for (int j = 2; j <= k; j++) {
        cht.init();
        for (int i = j; i < n; i++) {
            cht.update(Line(-ps[i-1], dp[i-1][j-1], i-1));
            dp[i][j] = ps[i]*(ps[n]-ps[i])+cht.query(ps[n]-ps[i]);
            track[i][j] = temp;
        }
    }
    int ans = k;
    for (int i = k; i < n; i++){
        if (dp[i][k] > dp[ans][k]) ans = i;
    }
    vector<int> tr;
    cout << dp[ans][k] << "\n";
    tr.pb(ans);
    while (k > 1) {
        ans = track[ans][k];
        --k;
        tr.push_back(ans);
    }
    for (int i = (int)tr.size()-1; i >= 0; i--) {
        cout << tr[i] << ' ';
    }
}
/*
7 3
4 1 3 4 0 2 3
*/

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