Submission #1028214

#	Time	Username	Problem	Language	Result	Execution time	Memory
1028214		Issa	Fire (BOI24_fire)	C++17	100 / 100	69 ms	38968 KiB

Main

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define ent "\n"

const int maxn = 1e6 + 100;
const ll INF = (ll)1e18 + 100;
const int inf = 1e9 + 100;
const int MOD = 1e9 + 7;
const int maxl = 20;
const int P = 31;

int n, m;
pii a[maxn];
int p[maxl][maxn];

void test(){
	cin >> n >> m;
	vector<pii> v;
	for(int i = 1; i <= n; i++){
		cin >> a[i].first >> a[i].second;
		if(a[i].second < a[i].first) a[i].second += m;
	}
	sort(a + 1, a + n + 1);
	for(int i = 1; i <= n; i++){
		v.push_back({a[i].second, i});
	}
	sort(v.begin(), v.end());
	int j = 0, mx = 0;
	for(auto [x, i]: v){
		while(j < n && a[j+1].first <= x){
			j++; if(!mx || a[mx].second < a[j].second) mx = j;
		}
		p[0][i] = mx;
	}
	for(int k = 1; k < maxl; k++){
		for(int i = 1; i <= n; i++){
			p[k][i] = p[k-1][p[k-1][i]];
		}
	}
	int ans = inf;
	for(int i = 1; i <= n; i++){
		int j = i, cnt = 0;
		for(int k = maxl - 1; k >= 0; k--){
			if(a[p[k][j]].second - a[i].first < m){
				j = p[k][j]; cnt += (1<<k);
			}
		}
		j = p[0][j]; cnt++;
		if(a[j].second - a[i].first >= m){
			ans = min(ans, cnt + 1);
		}
	}
	if(ans == inf) ans = -1;
	cout << ans;
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int t; t = 1;
    while(t--) test();
    cout << ent;
}

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