Submission #159081

#	Time	Username	Problem	Language	Result	Execution time	Memory
159081		mrboorger	Bigger segments (IZhO19_segments)	C++17	100 / 100	529 ms	46364 KiB

segments

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
//#include "interactive.h"

#define pb push_back
#define F first
#define S second
#define ll long long
#define ld long double
#define sqr(x) (x) * (x)
//#define all(a) a.begin(), a.end()

using namespace std;

const int maxn = 500005;
const ll inf = 1e18;

vector <pair <int, ll>> dp[maxn];
int a[maxn];
ll sum[maxn];

ll f(int l, int r)
{
    return sum[r] - (l > 0 ? sum[l - 1] : 0);
}

int main()
{
#ifdef LOCAL
//    freopen("input.txt", "r", stdin);
//    freopen("output.txt", "w", stdout);
#endif // LOCAL
//    ios_base::sync_with_stdio(0);
//    cin.tie(0);
//    cout.tie(0);
    int n;
    cin >> n;
    for(int i = 0; i < n; ++i)
    {
        cin >> a[i];
        sum[i] = a[i] + (i > 0 ? sum[i - 1] : 0);
    }
    for(int i = 0; i < n; ++i)
    {
        dp[i].pb({0, inf});
        dp[i].pb({0, inf});
    }
    dp[0][0] = {1, a[0]};
    for(int i = 0; i < n - 1; ++i)
        for(int j = 0; j < 2; ++j)
    {
        if (dp[i][j].S == inf) continue;
        if (dp[i][j].F > dp[i + 1][0].F)
        {
            swap(dp[i + 1][0], dp[i + 1][1]);
            dp[i + 1][0] = {dp[i][j].F, dp[i][j].S + a[i + 1]};
        }
        else
        if (dp[i][j].F == dp[i + 1][0].F && dp[i][j].S + a[i + 1] < dp[i + 1][0].S)
        {
            dp[i + 1][0].S = dp[i][j].S + a[i + 1];
        }
        else
        if (dp[i][j].F > dp[i + 1][1].F)
        {
            dp[i + 1][1] = {dp[i][j].F, dp[i][j].S + a[i + 1]};
        }
        else
        if (dp[i][j].F == dp[i + 1][1].F && dp[i][j].S + a[i + 1] < dp[i + 1][1].S)
        {
            dp[i + 1][1].S = dp[i][j].S + a[i + 1];
        }

        {
            int l = i + 1, r = n - 1;
            int b = n + 1;
            while(l <= r)
            {
                int m = (l + r) / 2;
                if (f(i + 1, m) >= dp[i][j].S)
                {
                    b = min(b, m);
                    r = m - 1;
                }
                else
                {
                    l = m + 1;
                }
            }
            if (b < n + 1)
            {
                if (dp[i][j].F + 1 > dp[b][0].F)
                {
                    swap(dp[b][0], dp[b][1]);
                    dp[b][0] = {dp[i][j].F + 1, f(i + 1, b)};
                }
                else
                if (dp[i][j].F + 1 == dp[b][0].F && f(i + 1, b) < dp[b][0].S)
                {
                    dp[b][0].S = f(i + 1, b);
                }
                else
                if (dp[i][j].F + 1 > dp[b][1].F)
                {
                    dp[b][1] = {dp[i][j].F + 1, f(i + 1, b)};
                }
                else
                if (dp[i][j].F + 1 == dp[b][1].F && f(i + 1, b) < dp[b][1].S)
                {
                    dp[b][1].S = f(i + 1, b);
                }
            }
        }
    }
    cout << max(dp[n - 1][0].F, dp[n - 1][1].F) << endl;
    return 0;
}

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