Submission #258079

#	Time	Username	Problem	Language	Result	Execution time	Memory
258079		aggu_01000101	Split the sequence (APIO14_sequence)	C++14	0 / 100	398 ms	131076 KiB

sequence

#include <iostream>
#include <assert.h>
#include <algorithm>
#include <vector>
#include <set>
#include <string>
#include <queue>
#include <map>
#include <bits/stdc++.h>
#define initrand mt19937 mt_rand(time(0));
#define rand mt_rand()
#define int long long
#define INF 10000000000000000
using namespace std;
#define mid(l, u) ((l+u)/2)
//#define cin fin
//#define cout fout
const int N = 100005;
const int K = 205;
int a[N];
int pref[N], suff[N];
int n, k;
int dp[K][N];
int nxt[K][N];
void f(int currk, int l, int r, int ll, int rr){ //dp(currk, m) = best cost when you want to make currk splits with first split starting at m
    if(l>r) return;
    int m = mid(l, r);
    //we want to calculate dp[currk][m]
    //look at dp[currk-1][max(ll, m+1)] to dp[currk - 1][min(rr, n - currk)].
    //The answer for dp[curr-1][x] will be (sum(m to x-1) * sum(x to n)) + dp[curr-1][x]
    //base case - dp[0][anything] = 0;
    int best = 0;
    //cout<<currk<<" "<<m<<" "<<ll<<" "<<rr<<endl;
    for(int x = max(ll, m+1);x<=min(rr, n - currk);x++){
        int tempans = ((pref[x-1] - pref[m-1]) * (pref[n] - pref[x-1])) + dp[currk - 1][x];
        //cout<<"ANS AT "<<x<<" is "<<tempans<<endl;
        if(tempans >= dp[currk][m]){
            nxt[currk][m] = x;
            dp[currk][m] = tempans;
        }
    }
    //cout<<"dp["<<currk<<"]["<<m<<"] = "<<dp[currk][m]<<endl;
    f(currk, l, m-1, ll, nxt[currk][m]);
    f(currk, m+1, r, nxt[currk][m], rr);
}
signed main(){
    //ofstream fin("2.in");
    //ofstream fout("2.out");
    cin>>n>>k;
    for(int i = 1;i<=n;i++) cin>>a[i];
    for(int i = 1;i<=n;i++) pref[i] = pref[i-1] + a[i];
    for(int i = n;i>=1;i--) suff[i] = suff[i+1] + a[i];
    for(int currk = 1;currk<=k;currk++){
        f(currk, 1, n - currk, 1, n);
    }
    cout<<dp[k][1]<<endl;
    int lol = k;
    int currst = 1;
    while(lol){
        cout<<(nxt[lol][currst] - 1)<<" ";
        currst = nxt[lol][currst];
        lol--;
    }
    cout<<endl;
}
/*
7 3
4 1 3 4 0 2 3
 */

Compilation message (stderr)

sequence.cpp: In function 'void f(long long int, long long int, long long int, long long int, long long int)':
sequence.cpp:32:9: warning: unused variable 'best' [-Wunused-variable]
     int best = 0;
         ^~~~

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