Submission #868926

#	Time	Username	Problem	Language	Result	Execution time	Memory
868926		mgl_diamond	Matryoshka (JOI16_matryoshka)	C++17	100 / 100	326 ms	26540 KiB

matryoshka

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ii = pair<int, int>;
template<class T> using vec = vector<T>;
 
#define foru(i, l, r) for(int i=(l); i<=(r); ++i)
#define ford(i, l, r) for(int i=(l); i>=(r); --i)
#define fore(x, v) for(auto &x : v)
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
#define fi first
#define se second
#define file "input"
 
void setIO(string name="") {
  ios::sync_with_stdio(0);
  cin.tie(0); cout.tie(0);
  if (fopen(file".in", "r")) {
    freopen(file".in", "r", stdin);
    freopen(file".out", "w", stdout);
  }
}

const int N = 2e5+5;
int n, m, ft[N], dp[N], fst[N*4], ret[N];
vector<int> comp;
ii a[N];

void modify(int i, int v) {
	for(i=n-i+1; i<=n; i+=i&-i) ft[i] = max(ft[i], v);
}

int query(int i) {
	int ans = 0;
	for(i=n-i+1; i>=1; i-=i&-i) ans = max(ans, ft[i]);
	return ans;
}

int main() {
	setIO();
	cin >> n >> m;
	foru(i, 1, n) {
		cin >> a[i].fi >> a[i].se;
		comp.push_back(a[i].fi);
		comp.push_back(a[i].se);
	}

	vector<pair<ii, int>> querys;
	foru(i, 1, m) {
		int d, h;
		cin >> d >> h;
		querys.push_back({{h, d}, i});
		comp.push_back(d);
		comp.push_back(h);
	}

	sort(all(comp));
	comp.resize(unique(all(comp)) - comp.begin());

	foru(i, 1, n) {
		a[i].fi = upper_bound(all(comp), a[i].fi) - comp.begin();
		a[i].se = upper_bound(all(comp), a[i].se) - comp.begin();
	}

	fore(x, querys) {
		x.fi.fi = upper_bound(all(comp), x.fi.fi) - comp.begin();
		x.fi.se = upper_bound(all(comp), x.fi.se) - comp.begin();
	}

	sort(a+1, a+n+1, [&](ii a, ii b){
		return a.fi < b.fi || (a.fi == b.fi && a.se > b.se);
	});

	vector<int> lis;
	vector<ii> updates;

	ford(i, n, 1) {
		int it = upper_bound(all(lis), a[i].se) - lis.begin();
		if (it == sz(lis)) lis.push_back(a[i].se);
		else lis[it] = a[i].se;
		fst[a[i].fi] = i;
		dp[i] = it+1;
		updates.emplace_back(a[i].se, i);
	}

	fst[sz(comp)+1] = n+1;
	ford(i, sz(comp), 1) if (fst[i] == 0) fst[i] = fst[i+1];
	
	sort(all(querys));
	sort(all(updates));

	int j = 0, k = 0;
	foru(i, 1, sz(comp)) {
		while (j < sz(updates) && updates[j].fi <= i) {
			int p = updates[j].se;
			modify(p, dp[p]);
			++j;
		}

		while (k < sz(querys) && querys[k].fi.fi <= i) {
			int p = fst[querys[k].fi.se];
			ret[querys[k].se] = query(p);
			++k;
		}
	}

	foru(i, 1, m) {
		cout << ret[i] << "\n";
	}
}

Compilation message (stderr)

matryoshka.cpp: In function 'void setIO(std::string)':
matryoshka.cpp:20:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |     freopen(file".in", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
matryoshka.cpp:21:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 |     freopen(file".out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 15 / 15
• Subtask 3: 25 / 25
• Subtask 4: 49 / 49