Submission #868734

#	Time	Username	Problem	Language	Result	Execution time	Memory
868734		alexdd	Bigger segments (IZhO19_segments)	C++17	13 / 100	7 ms	31576 KiB

segments

#include<bits/stdc++.h>
using namespace std;
#define int long long
const int INF = 1e9;
int n;
int a[500005];
int dp[500005];
int ult[500005];
int pref[500005];
set<pair<int,int>> rez[500005];
void getrez(int x, int i)
{
    if(rez[x].empty())
        return;
    auto it = rez[x].upper_bound({pref[i], INF});
    if(it==rez[x].begin())
        return;
    it--;
    pair<int,int> cop = *it;
    if(x+1>dp[i] || (x+1==dp[i] && pref[i]-pref[cop.second]<ult[i]))
    {
        dp[i]=x+1;
        ult[i]=pref[i]-pref[cop.second];
    }
}
signed main()
{
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        cin>>a[i];
        pref[i]=pref[i-1]+a[i];
    }
    dp[0]=0;
    ult[0]=0;
    rez[0].insert({0,0});
    for(int i=1;i<=n;i++)
    {
        dp[i]=dp[i-1];
        ult[i]=ult[i-1]+a[i];
        /**for(int x=i-1;x>=0;x--)
        {
            if(dp[x]+1<=dp[i])
                break;
            if(ult[x]+pref[x]<=pref[i])
            {
                dp[i]=dp[x]+1;
                ult[i]=pref[i]-pref[x];
            }
        }*/

        getrez(dp[i]-1,i);
        getrez(dp[i],i);

        rez[dp[i]].insert({ult[i]+pref[i],i});
        /*if(dp[i-1]>dp[i] || (dp[i-1]==dp[i] && ult[i-1]+a[i]<ult[i]))
        {
            dp[i]=dp[i-1];
            ult[i]=ult[i-1]+a[i];
        }*/
    }
    cout<<dp[n];
    return 0;
}
/**

dp[i] = numarul maxime de secvente in care pot fi impartite primele i elemente
ult[i] = suma ultimei secvente din solutia pt dp[i]
dp[i] max= dp[i-1]
dp[i] max= max(dp[x]+1) pt x = 0..i-1 && ult[x] + pref[x] <= pref[i]


*/

• Subtask 1: 13 / 13
• Subtask 2: 0 / 14
• Subtask 3: 0 / 10
• Subtask 4: 0 / 36
• Subtask 5: 0 / 27