Submission #1301249

#	Time	Username	Problem	Language	Result	Execution time	Memory
1301249		Thanhs	Lasers (NOI19_lasers)	C++20	100 / 100	92 ms	7872 KiB

lasers

#pragma GCC optimze("Ofast,unroll-loops")
#include <bits/stdc++.h>
using namespace std;

#define name "TENBAI"
#define fi first
#define se second
#define endl '\n'
#define setmin(x, y) x = min((x), (y))
#define setmax(x, y) x = max((x), (y))
#define sqr(x) ((x) * (x))
#define all(x) x.begin(), x.end()

mt19937 hdp(chrono::high_resolution_clock::now().time_since_epoch().count());
int rand(int l, int r){return l + ((hdp() % (r - l + 1)) + r - l + 1) % (r - l + 1);}

int L, n;
vector<pair<int, int>> V;

bool its(pair<int, int> x, pair<int, int> y)
{
    return min(x.se, y.se) >= max(x.fi, y.fi);
}

void solve()
{
    cin >> L >> n;
    while (n--)
    {
        int t;
        cin >> t;
        vector<int> a;
        while (t--)
        {
            int x;
            cin >> x;
            a.push_back(x);
        }
        int miss = L - accumulate(all(a), 0);
        vector<pair<int, int>> v;
        int sum = 0;
        v.push_back({sum + 1, sum + miss});
        for (int x : a)
        {
            sum += x;
            v.push_back({sum + 1, sum + miss});
        }
        int pr = 0;
        sort(all(v));
        for (int i = 0; i < v.size(); i++)
        {
            int l = v[i].fi, r = v[i].se;
            int j = i;
            while (j + 1 < v.size() && its({l, r}, v[j + 1]))
            {
                j++;
                setmin(l, v[j].fi);
                setmax(r, v[j].se);
            }  
            i = j;
            if (pr + 1 <= l - 1)
                V.emplace_back(pr + 1, l - 1);
            pr = r;
        }
        if (pr + 1 <= L)
            V.emplace_back(pr + 1, L);
    }
    int pr = 0, ans = 0;
    sort(all(V));
    for (int i = 0; i < V.size(); i++)
    {
        int l = V[i].fi, r = V[i].se;
        int j = i;
        while (j + 1 < V.size() && its({l, r}, V[j + 1]))
        {
            j++;
            setmin(l, V[j].fi);
            setmax(r, V[j].se);
        }
        i = j;
        ans += l - pr - 1;
        pr = r;
    }
    ans += L - pr;
    cout << L - ans;
}

signed main()
{
    if (fopen("in.txt", "r")) 
    {
        freopen("in.txt", "r", stdin);
        freopen("out.txt", "w", stdout);
    }
    else if (fopen(name".inp", "r"))
    {
        freopen(name".inp", "r", stdin);
        freopen(name".out", "w", stdout);
    }
    ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
    int tc = 1; 
    // cin >> tc;
    while (tc--)
        solve();
}

Compilation message (stderr)

lasers.cpp: In function 'int main()':
lasers.cpp:92:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   92 |         freopen("in.txt", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
lasers.cpp:93:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   93 |         freopen("out.txt", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
lasers.cpp:97:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   97 |         freopen(name".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
lasers.cpp:98:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   98 |         freopen(name".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 14 / 14
• Subtask 3: 20 / 20
• Subtask 4: 21 / 21
• Subtask 5: 22 / 22
• Subtask 6: 13 / 13