Submission #1184474

#	Time	Username	Problem	Language	Result	Execution time	Memory
1184474		Haanhtien	Bigger segments (IZhO19_segments)	C++17	100 / 100	40 ms	23880 KiB

segments

#include<bits/stdc++.h>
using namespace std;

#define ll long long
#define FOR(i, a, b) for(int i=(a), _b=(b); i<=_b; i++)
#define FORD(i, a, b) for(int i=(a), _b=(b); i>=_b; i--)
#define BIT(i, j) ((i>>j)&1)
#define pb push_back
#define ii pair<ll, ll>
#define pii pair<ll, ii>
#define all(x) x.begin(), x.end()
#define fi first
#define se second

const ll inf = 1e18;
const ll mod = 1e9+7;
const ll N = 500005;
const ll M = 50005;

int n;
ll a[N], pre[N];
int num;
ii dq[N];
ii f[N];
void solve()
{
    cin >> n;
    for (int i = 1; i <= n; i++)
    {
        cin >> a[i];
        pre[i] = pre[i - 1] + a[i];
    }
    dq[0] = {0, 0};
    int j = 0;
    for (int i = 1; i <= n; i++)
    {
        while (j < num && dq[j + 1].fi <= pre[i]) j++;
        
        //cout << x << ' ' << id << '\n';
        int id = dq[j].se;
        f[i] = {f[id].fi + 1, pre[i] - pre[id]};
        //0cout << f[i].fi << ' ' << f[i].se << '\n';
        while (f[i].se + pre[i] <= dq[num].fi) num--;
        dq[++num] = {f[i].se + pre[i], i};
        j = min(j, num);
        
    }
    cout << f[n].fi;
}
int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    #define task "task"
    if(fopen(task".inp", "r"))
    {
        freopen(task".INP", "r", stdin);
        freopen(task".OUT", "w", stdout);
    }
    solve();
    return 0;
}

Compilation message (stderr)

segments.cpp: In function 'int main()':
segments.cpp:56:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   56 |         freopen(task".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
segments.cpp:57:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   57 |         freopen(task".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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