Submission #1169596

#	Time	Username	Problem	Language	Result	Execution time	Memory
1169596		Thanhs	Curtains (NOI23_curtains)	C++20	0 / 100	0 ms	328 KiB

curtains

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

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

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);}

const int NM = 5e5 + 5;
const int LG = 20;
const int inf = 1e9;

int n, m, q, up[NM][LG], dt[NM], mn[NM];
pair<int, int> a[NM];

void upd(int i, int v)
{
    i = n - i + 1;
    for (; i <= n; i += i & -i)
        setmin(dt[i], v);
}

int get(int i)
{
    i = n - i + 1;
    int res = inf;
    for (; i; i -= i & -i)
        setmin(res, dt[i]);
    return res;
}

void solve()
{
    cin >> n >> m >> q;
    fill(dt + 1, dt + 1 + n, inf);
    fill(mn + 1, mn + 1 + n, inf);
    for (int i = 1; i <= m; i++)
        cin >> a[i].fi >> a[i].se;
    sort(a + 1, a + 1 + m, [&](const auto x, const auto y){return make_pair(x.se, x.fi) < make_pair(y.se, y.fi);});
    for (int i = m; i >= 1; i--)
    {
        setmin(mn[a[i].fi], i);
        up[i][0] = get(a[i].fi);
        for (int j = 1; j < LG; j++)
            up[i][j] = (up[i][j - 1] == inf ? inf : up[up[i][j - 1]][j - 1]);
        upd(a[i].fi, i);
    }
    while (q--)
    {
        int l, r;
        cin >> l >> r;
        int t = mn[l];
        if (t == inf)
            cout << "NO\n";
        else
        {
            for (int i = LG - 1; i >= 0; i--)
                if (up[t][i] != inf && a[up[t][i]].se <= r)
                    t = up[t][i];
            cout << (a[t].se == r ? "YES\n" : "NO\n");
        }
    }
}

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)

curtains.cpp: In function 'int main()':
curtains.cpp:76:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   76 |         freopen("in.txt", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
curtains.cpp:77:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |         freopen("out.txt", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
curtains.cpp:81:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   81 |         freopen(name".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
curtains.cpp:82:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   82 |         freopen(name".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 3
• Subtask 2: 0 / 6
• Subtask 3: 0 / 15
• Subtask 4: 0 / 20
• Subtask 5: 0 / 36
• Subtask 6: 0 / 20