Submission #1103490

#	Time	Username	Problem	Language	Result	Execution time	Memory
1103490		hqminhuwu	Fire (BOI24_fire)	C++14	100 / 100	230 ms	88264 KiB

Main

#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair <ll,ll> pll;
typedef pair <int,int> pii;
typedef pair <int,pii> piii;

#define forr(_a,_b,_c) for(int _a = (_b); _a <= int (_c); ++_a)
#define ford(_a,_b,_c) for(int _a = (_b) + 1; _a --> int (_c);)
#define forf(_a,_b,_c) for(int _a = (_b); _a < int (_c); ++_a)
#define st first
#define nd second
#define pb push_back
#define mp make_pair
#define all(x) begin(x),end(x)
#define mask(i) (1LL << (i))
#define bit(x, i) (((x) >> (i)) & 1)
#define bp __builtin_popcountll
#define file "test"

template<class X, class Y>
	bool minz(X &x, const Y &y) {
		if (x > y) {
			x = y;
			return true;
		} return false;
	}
template<class X, class Y>
	bool maxz(X &x, const Y &y) {
		if (x < y) {
			x = y;
			return true;
		} return false;
	}

const int N = 5e5 + 5;
const ll oo = (ll) 1e16;
const ll mod = 1e9 + 7; // 998244353;

int n, m;
pii a[N];
namespace sub6 {
	map <int, vector<pii>> qq;
	set <pii> s;
	int ans = mod, up[20][N];

	void solve(){
		forr (i, 1, n){
			qq[a[i].nd].pb({1, i});
			qq[a[i].st].pb({0, i});
		}

		for (pair<int, vector<pii>> ww : qq){
			int u = ww.st;
			vector <pii> v = ww.nd;

			sort(all(v));

			for (pii e : v){
				if (e.st == 0){
					s.insert(mp(a[e.nd].nd, e.nd));
				} else {
					s.erase(s.find(mp(a[e.nd].nd, e.nd)));
					if (s.size()){
						up[0][e.nd] = (*s.rbegin()).nd;
					} else {
						up[0][e.nd] = n + 1;
					}
				}
			}
		}

		a[n + 1].nd = 2 * m + 1;

		forr (i, 0, 17){
			up[i][n + 1] = n + 1;
		}

		ford (i, n, 1){
            if (up[0][i] < i) continue;
			forr (j, 1, 17){
				up[j][i] = up[j - 1][up[j - 1][i]];
			}

			int u = i, res = 2;
			
			ford (j, 17, 0){
				if (a[up[j][u]].nd < a[i].st + m){
					res += mask(j);
					u = up[j][u];
				}
			}
        

			if (up[0][u] != n + 1 && a[up[0][u]].nd >= a[i].st + m){
				minz(ans, res);
			}
		}

		cout << (ans <= n ? ans : -1) << "\n";
	}
}

namespace sub2 {
	int f[500], ans = mod;

	void solve(){
		forr (i, 1, n){
			memset (f, 63, sizeof f);
			
			forr (j, 1, n){
				if (a[j].st == a[i].st){
					f[j] = 1;
				} else {
					ford (k, j - 1, 1){
						if (a[j].st >= a[k].st && a[j].st <= a[k].nd){
							minz(f[j], f[k] + 1);
						}
					}
				}
				if (a[j].nd >= a[i].st + m){
					minz(ans, f[j]);
				}
			}
		}

		cout << (ans <= n ? ans : -1) << "\n";
	}
}

int main(){
	ios_base::sync_with_stdio(0); cin.tie(0);
	#ifdef kaguya
		freopen(file".inp", "r", stdin); freopen(file".ans", "w", stdout);
	#endif

	cin >> n >> m;

	forr (i, 1, n){
		cin >> a[i].st >> a[i].nd;
	
		if (a[i].nd < a[i].st)
			a[i].nd += m;
	}

	sort(a + 1, a + 1 + n);

	if (n <= 300){
		sub2::solve();
	} else {
		sub6::solve();
	}

	return 0;
}
/*



*/

Compilation message (stderr)

Main.cpp: In function 'void sub6::solve()':
Main.cpp:55:8: warning: unused variable 'u' [-Wunused-variable]
   55 |    int u = ww.st;
      |        ^

• Subtask 1: 14 / 14
• Subtask 2: 17 / 17
• Subtask 3: 9 / 9
• Subtask 4: 13 / 13
• Subtask 5: 21 / 21
• Subtask 6: 26 / 26