Submission #955828

#	Time	Username	Problem	Language	Result	Execution time	Memory
955828		Yang8on	Bigger segments (IZhO19_segments)	C++14	73 / 100	1562 ms	240740 KiB

segments

#include <bits/stdc++.h>
#define gsn "Bigger segments"
#define ll long long
#define pii pair<int, ll>
#define gb(i, j) ((i >> j) & 1)
#define fi(i, a, b) for(int i = a; i <= b; i++)
#define fid(i, a, b) for(int i = a; i >= b; i--)

using namespace std;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll GetRandom(ll l, ll r)
{
    return uniform_int_distribution<ll> (l, r) (rng);
}

const int maxn = 500005;
const ll mx = 500000000000000;

int n;
int a[maxn];
ll s[maxn];
pii dp[maxn];

map<ll, pii> bit;

void update(ll x, pii val)
{
    while(x <= mx)
    {
        bit[x] = max(bit[x], val);
        x += (x & -x);
    }
}

pii get(ll x)
{
    pii best = {0, 1e18};
    while(x)
    {
        best = max(best, bit[x]);
        x -= (x & -x);
    }

    return best;
}

void solve()
{
    cin >> n;
    fi(i, 1, n) cin >> a[i], s[i] = s[i - 1] + a[i];

    fi(i, 1, n) dp[i] = {0, 1e18};

    dp[0] = {0, 0};
    update(dp[0].second + s[0] + 1, make_pair(dp[0].first + 1, s[0] + 1));

    fi(i, 1, n)
    {
        pii best = get(s[i] + 1);
        dp[i] = {best.first, s[i] + 1 - best.second};
        update(dp[i].second + s[i] + 1, make_pair(dp[i].first + 1, s[i] + 1));
//        fi(j, 0, i - 1)
//        {
//            if(s[i] - s[j] >= dp[j].second)
//            {
//                if(dp[j].first + 1 >= dp[i].first)
//                {
//                    dp[i].first = dp[j].first + 1;
//                    dp[i].second = min(dp[i].second, s[i] - s[j]);
//                }
//            }
//        }
    }

    cout << dp[n].first;
}


int main()
{
    if(fopen(gsn".inp", "r"))
    {
        freopen(gsn".inp", "r", stdin);
        freopen(gsn".out", "w", stdout);
    }

    ios_base::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);

    int nTest = 1;
//    cin >> nTest;

    while(nTest --)
    {
        solve();
    }




    /// ------------------check time!-----------------///
    cerr << "\n" << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
    return 0;
}

Compilation message (stderr)

segments.cpp: In function 'int main()':
segments.cpp:84:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   84 |         freopen(gsn".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
segments.cpp:85:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   85 |         freopen(gsn".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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