oj.uz

Submission #159067

# Submission time Handle Problem Language Result Execution time Memory
159067 2019-10-20T12:46:28 Z mrboorger Bigger segments (IZhO19_segments) C++17
0 / 100
 2 ms 376 KB 
#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 = 3005;
const ll inf = 1e18;

ll dp[maxn][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)
        for(int j = 0; j <= i + 1; ++j)
            dp[i][j] = inf;
    dp[0][1] = a[1];
    for(int i = 0; i < n - 1; ++i)
        for(int j = 0; j <= i + 1; ++j)
    {
        if (dp[i][j] == inf) continue;
        dp[i + 1][j] = min(dp[i + 1][j], dp[i][j] + a[i + 1]);
        {
            int l = i + 1, r = n;
            int b = n + 1;
            while(l <= r)
            {
                int m = (l + r) / 2;
                if (f(i + 1, m) >= dp[i][j])
                {
                    b = min(b, m);
                    r = m - 1;
                }
                else
                {
                    l = m + 1;
                }
            }
            if (b < n + 1)
            {
                dp[b][j + 1] = min(dp[b][j + 1], f(i + 1, b));
            }
        }
    }
    int ans = 0;
    for(int j = 1; j <= n; ++j)
        if (dp[n - 1][j] != inf) ans = j;
    cout << ans << endl;
    return 0;
}

Subtask #1
0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Incorrect 2 ms 348 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Incorrect 2 ms 348 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #3
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Incorrect 2 ms 348 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #4
0 / 36.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Incorrect 2 ms 348 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #5
0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Incorrect 2 ms 348 KB Output isn't correct
3 Halted 0 ms 0 KB -