Submission #384261

#	Time	Username	Problem	Language	Result	Execution time	Memory
384261		danielcm585	Split the sequence (APIO14_sequence)	C++14	100 / 100	1492 ms	81900 KiB

sequence

#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second

typedef long long ll;
typedef pair<int,int> ii;

const int N = 1e5;
const int K = 2e2;
const ll INF = 1e18;
int n, k;
int a[N+2];
int bt[K+2][N+2];
ll sum[N+2];
ll dp[2][N+2];

ll cost(int l, int r) {
    return (sum[r]-sum[l-1])*sum[l-1];
}

void compute(int id, int l, int r, int x, int y) {
    if (l > r) return;
    int mid = (l+r)/2, opt = -1;
    dp[id&1][mid] = -INF;
    for (int i = x; i <= min(y,mid); i++) {
        if (dp[id&1][mid] < dp[id&1^1][i-1]+cost(i,mid)) {
            dp[id&1][mid] = dp[id&1^1][i-1]+cost(i,mid);
            bt[id][mid] = i-1;
            opt = i;
        }
    }
    compute(id,l,mid-1,x,opt); compute(id,mid+1,r,opt,y);
}

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    cin >> n >> k; k++;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        sum[i] = sum[i-1]+a[i];
    }
    for (int i = 2; i <= k; i++) compute(i,i,n,i,n);
    vector<int> res;
    for (int i = n, j = k; i >= 1; i = bt[j][i], j--) {
        res.push_back(bt[j][i]);
    }
    sort(res.begin(),res.end());
    cout << dp[k&1][n] << '\n';
    for (int i = 1; i < res.size(); i++) {
        if (i != 1) cout << ' ';
        cout << res[i];
    }
    cout << '\n';
    return 0;
}

/*
7 3
4 1 3 4 0 2 3
*/

Compilation message (stderr)

sequence.cpp: In function 'void compute(int, int, int, int, int)':
sequence.cpp:28:34: warning: suggest parentheses around arithmetic in operand of '^' [-Wparentheses]
   28 |         if (dp[id&1][mid] < dp[id&1^1][i-1]+cost(i,mid)) {
      |                                ~~^~
sequence.cpp:29:34: warning: suggest parentheses around arithmetic in operand of '^' [-Wparentheses]
   29 |             dp[id&1][mid] = dp[id&1^1][i-1]+cost(i,mid);
      |                                ~~^~
sequence.cpp: In function 'int main()':
sequence.cpp:51:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   51 |     for (int i = 1; i < res.size(); i++) {
      |                     ~~^~~~~~~~~~~~

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