Submission #406747

#	Time	Username	Problem	Language	Result	Execution time	Memory
406747		JerryLiu06	Split the sequence (APIO14_sequence)	C++17	0 / 100	71 ms	131076 KiB

sequence

#include <bits/stdc++.h>
 
using namespace std;
 
using ll = long long;
using db = long double;
using str = string;
 
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;
 
using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vd = vector<db>;
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>;
using vpd = vector<pd>;
 
#define mp make_pair
#define f first
#define s second

#define sz(x) (int)(x).size()
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define sor(x) sort(all(x))
#define ft front()
#define bk back()
#define pb push_back
#define pf push_front
 
#define lb lower_bound
#define ub upper_bound
 
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define F0R(i, a) FOR(i, 0, a)
#define ROF(i, a, b) for (int i = (b) - 1; i >= (a); i--)
#define R0F(i, a) ROF(i, 0, a)
#define EACH(a, x) for (auto& a : x)

const int MOD = 1e9 + 7;
const int MXN = 1e5 + 10;
const int MXK = 210;
const ll INF = 1e18;

using ld = long double;

int N, K; ll S[MXN], DP[MXN][2], ans[MXN][MXK];

ld isect(int A, int B, int i) {
    return (ld) (S[A] * S[A] + DP[A][i] - S[B] * S[B] - DP[B][i]) / (ld) (2 * S[A] - 2 * S[B]); 
}

int main() {
    ios_base::sync_with_stdio(false); cin.tie(0);

    cin >> N >> K; FOR(i, 1, N + 1) { int A; cin >> A; S[i] = A + S[i - 1]; }

    DP[0][0] = 0; FOR(i, 1, N + 1) DP[i][0] = INF;

    FOR(j, 1, K + 2) {
        deque<int> Q; Q.pb(0); FOR(i, 1, N + 1) {
            while (sz(Q) > 1 && isect(Q[0], Q[1], (j - 1) % 2) <= S[i]) Q.pop_front();

            int cur = Q.front(); DP[i][j % 2] = DP[cur][(j - 1) % 2] + (S[i] - S[cur]) * (S[i] - S[cur]); ans[i][j] = cur;

            while (sz(Q) > 1 && isect(Q[sz(Q) - 2], Q.back(), (j - 1) % 2) > isect(Q.back(), i, (j - 1) % 2)) Q.pop_back(); Q.pb(i);
        }
    }
    cout << (S[N] * S[N] - DP[N][(K + 1) % 2]) / 2 << "\n"; int ind = N;

    ROF(i, 2, K + 2) { ind = ans[ind][i]; cout << ind << " "; }
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:70:13: warning: this 'while' clause does not guard... [-Wmisleading-indentation]
   70 |             while (sz(Q) > 1 && isect(Q[sz(Q) - 2], Q.back(), (j - 1) % 2) > isect(Q.back(), i, (j - 1) % 2)) Q.pop_back(); Q.pb(i);
      |             ^~~~~
sequence.cpp:70:125: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'while'
   70 |             while (sz(Q) > 1 && isect(Q[sz(Q) - 2], Q.back(), (j - 1) % 2) > isect(Q.back(), i, (j - 1) % 2)) Q.pop_back(); Q.pb(i);
      |                                                                                                                             ^

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