Submission #732630

#	Time	Username	Problem	Language	Result	Execution time	Memory
732630		ac2hu	Split the sequence (APIO14_sequence)	C++14	71 / 100	72 ms	131072 KiB

sequence

#include<bits/stdc++.h>
using namespace std;
#define int long long 
using ll = long long;
const int N = 1e5 + 10;
const int K = 200 + 10;
int n, k, a[N], dp[N][K], b[N][K];
struct line {
    long long m, c, id;
    long long eval(long long x) { return m * x + c; }
    long double intersectX(line l) { return (long double) (c - l.c) / (l.m - m); }
};
signed main(){
    iostream::sync_with_stdio(false);cin.tie(nullptr);
    cin >> n >> k;
    for(int i = 1;i<=n;i++)cin >> a[i];
    for(int i = 1;i<=n;i++)a[i] += a[i - 1];
    for(int l = 1;l<=k;l++){
        deque<line> dq;dq.push_front({0, 0, 0});
        for(int i = 1;i<=n;i++){
            if(i > l){
                while(dq.size() >= 2 && dq.back().eval(a[i]) <= dq[dq.size() -2].eval(a[i]))dq.pop_back(); 
                dp[i][l] = dq.back().eval(a[i]); b[i][l] = dq.back().id;
            }
            if(i > l - 1){
                line cur = {a[i], -a[i]*a[i] + dp[i][l - 1], i};
                while(dq.size() >= 2 && cur.intersectX(dq[0]) <= cur.intersectX(dq[1]))
                    dq.pop_front();
                dq.push_front(cur); 
            }
        }
    }
    cout << dp[n][k] << "\n";
    vector<int> v = {n}; 
    for(int l = k;l>=1;l--){
        v.push_back(b[v.back()][l]);
    }
    reverse(v.begin(), v.end());v.pop_back();reverse(v.begin(), v.end());
    for(int e : v)cout << e << " ";
    cout << "\n";
}

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