Submission #169367

#	Time	Username	Problem	Language	Result	Execution time	Memory
169367		SamAnd	Bigger segments (IZhO19_segments)	C++17	100 / 100	147 ms	18912 KiB

segments

#include <bits/stdc++.h>
using namespace std;
#define m_p make_pair
const int N = 500005;

int n;
int a[N];
long long p[N];

pair<int, long long> dp[N];

pair<int, long long> mer(const pair<int, long long>& l, const pair<int, long long>& r)
{
    if (l.first > r.first)
        return l;
    if (l.first < r.first)
        return r;
    if (l.second < r.second)
        return l;
    return r;
}

int main()
{
    scanf("%d", &n);
    for (int i = 1; i <= n; ++i)
        scanf("%d", &a[i]);
    for (int i = 1; i <= n; ++i)
        p[i] = p[i - 1] + a[i];
    for (int i = 0; i < n; ++i)
    {
        dp[i + 1] = mer(dp[i + 1], m_p(dp[i].first, dp[i].second + a[i + 1]));
        int l = i + 1, r = n;
        int ans = -1;
        while (l <= r)
        {
            int m = (l + r) / 2;
            if (p[m] - p[i] >= dp[i].second)
            {
                ans = m;
                r = m - 1;
            }
            else
                l = m + 1;
        }
        if (ans != -1)
            dp[ans] = mer(dp[ans], m_p(dp[i].first + 1, p[ans] - p[i]));
    }
    printf("%d\n", dp[n].first);
    return 0;
}

Compilation message (stderr)

segments.cpp: In function 'int main()':
segments.cpp:25:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
segments.cpp:27:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d", &a[i]);
         ~~~~~^~~~~~~~~~~~~

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