Submission #274900

#	Time	Username	Problem	Language	Result	Execution time	Memory
274900		toonewbie	Split the sequence (APIO14_sequence)	C++17	33 / 100	213 ms	131076 KiB

sequence

#include <bits/stdc++.h>

#define F first
#define S second
#define pb push_back
//#define endl '\n'
#define ll long long
#define pll pair<ll,ll>
#define pi pair<int,int>

using namespace std;

const int MOD = 1e9 + 7;
const ll INF = 1e18;
const int MAXN = 1e9+1;
const int N = 1005;

struct Line{
    ll m, b, id;
    ll eval(ll x) {
        return m*x + b;
    }
};
struct node{
    node *l, *r;
    Line ln;
    node(node* _l, node* _r, Line _ln):
        l(_l), r(_r), ln(_ln) {};
};
typedef node* pnode;

Line get(pnode rt) {
    return (!rt ? Line({0, -INF, -1}) : rt -> ln);
}
void add(pnode &rt, Line ln, int l=0, int r=MAXN, int v = 1) {
    if (!rt) rt = new node(NULL, NULL, Line({0, -INF, -1}));
    int m = (l + r) >> 1;
    bool left = ln.eval(l) > get(rt).eval(l);
    bool mid = ln.eval(m) > get(rt).eval(m);
    if (mid) swap(ln, rt -> ln);
    if (r - l == 1) return;
    if (left != mid) add(rt -> l, ln, l, m, v << 1);
    else add(rt -> r, ln, m, r, v << 1 | 1);
}

pll get(pnode &rt, ll x, int l=0, int r=MAXN, int v=1) {
    if (rt == NULL) rt = new node(NULL, NULL, Line({0, -INF, -1}));
    int m = (l + r) >> 1;
    pll now = {get(rt).eval(x), get(rt).id};
    if (r - l == 1) return now;
    if (x < m) return max(now, get(rt -> l, x, l, m, v << 1));
    else return max(now, get(rt -> r, x, m, r, v << 1 | 1));
}

ll dp[201][N];
int opt[201][N], ps[N];
pnode rt;
int main() {
    ios_base :: sync_with_stdio(0);
    cin.tie(0);
    int n, K;
    cin >> n >> K; K++;
    for (int i = 1, x; i <= n; i++) {
        cin >> x;
        ps[i] = ps[i - 1] + x;
        dp[0][i] = -INF;
    }
    dp[0][0] = 0;
    pll ans;
    for (int k = 1; k <= K; k++) {
        rt = NULL;
        if (k == 1) add(rt, Line({0, 0, 0}));
        for (int i = 1; i <= n; i++) {
            //cout << "getting ans for " << ps[i] << endl;
            ans = get(rt, ps[i]);
            dp[k][i] = ans.F;
            opt[k][i] = ans.S;
            //cout << k << " " << i << " " << opt[k][i] << endl;
            add(rt, Line({ps[i], dp[k - 1][i] - 1ll*ps[i]*ps[i], i}));
        }
    }
    cout << dp[K][n] << endl;
    vector<int> res;
    int id = n, ptr = K;
    while(res.size() < K - 1) {
        res.pb(opt[ptr][id]);
        id = opt[ptr--][id];
    }
    reverse(res.begin(), res.end());
    for (int i : res) cout << i << " ";
    return 0;
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:85:22: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   85 |     while(res.size() < K - 1) {
      |           ~~~~~~~~~~~^~~~~~~

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