Submission #1303581

#	Time	Username	Problem	Language	Result	Execution time	Memory
1303581		tminh	Fire (BOI24_fire)	C++20	0 / 100	15 ms	31904 KiB

Main

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

#define task ""
#define ll long long
#define endl '\n'
#define x first
#define y second
#define vall(a) (a).begin(), (a).end()
#define sze(a) (int)a.size()
#define pii pair<int, int>
#define pll pair<ll, ll>

#define ep emplace_back
#define pb push_back
#define pf push_front


const ll mod = 1e9 + 7;
const int N = 5e5 + 5;
const ll oo = 1e16;
const int LOG = 20;


pii cor[N];
vector<int> arr;
int n, m, t;

int up[N][LOG];
ll cost[N][LOG];

struct node {
	ll l, x;
	node(ll l_ = -oo, ll x_ = 0) : l(l_), x(x_) {}
	
	node operator+(const node &other) const {
		if (l > other.l || (l == other.l && x > other.x)) return *this;
		return other;
	}
};
	
struct ST {
	node st[N << 2];
	void update(int id, int l, int r, int i, ll val, ll pos) {
		if (l > i || r < i) return;
		if (l == r) {
			st[id] = st[id] + node(val, pos);
			return;
		}
		int mid = (l + r) >> 1;
		update(id << 1, l, mid, i, val, pos);
		update(id << 1 | 1, mid + 1, r, i, val, pos);
		st[id] = st[id << 1] + st[id << 1 | 1];
	}
	node get(int id, int l, int r, int u, int v) {
		if (l > v || r < u) return node();
		if (l >= u && r <= v) return st[id];
		
		int mid = (l + r) >> 1;
		return get(id << 1, l, mid, u, v) + get(id << 1 | 1, mid + 1, r, u, v);
	}
} st;


int sad[N];
namespace FN {
	void solve() {
		sort(vall(arr));
		arr.erase(unique(vall(arr)), arr.end());
		
		for (int i = 1; i <= 2 * n; ++i) {
			cor[i].x = lower_bound(vall(arr), cor[i].x) - arr.begin() + 1;
			cor[i].y = lower_bound(vall(arr), cor[i].y) - arr.begin() + 1;
		}
		t = sze(arr);
		for (int i = 1; i <= 2 * n; ++i) st.update(1, 1, t, cor[i].x, cor[i].y, i);
		
		
		for (int i = 1; i <= 2 * n; ++i) {
			node cur = st.get(1, 1, t, cor[i].x, cor[i].y);
			ll l = cur.l;
			ll x = cur.x;
			
			if (l == cor[i].y) {
				up[i][0] = i;
				cost[i][0] = 0;
			} else {
				up[i][0] = x;
				cost[i][0] = 1;
			}
		}
		for (int i = 1; i < LOG; ++i) {
			for (int j = 1; j <= 2 * n; ++j) {
				up[j][i] = up[up[j][i - 1]][i - 1];
				cost[j][i] = cost[j][i - 1] + cost[up[j][i - 1]][i - 1]; 
			}
		}
		
		ll res = oo;
		for (int t = 1; t <= 2 * n; ++t) {
			int cur = lower_bound(vall(arr), sad[t] + m) - arr.begin() + 1;
			int p = t;
			ll ans = 1;
			for (int i = LOG - 1; i >= 0; --i) {
				if (cor[up[p][i]].y <= cur) {
					ans += cost[p][i];
					p = up[p][i];
				}
			}
			if (cor[p].y >= cur) {
				res = min(res, ans);
			} else {
				p = up[p][0];
				if (cor[p].y >= cur) res = min(res, ans + 1);
			}
		}
		cout << (res == oo ? -1 : res) << endl;
		
		
		
	}
	
	
}


void input() {
	cin >> n >> m;
	for (int i = 1; i <= n; ++i) {
		
		int l, r;
		cin >> l >> r;
		
		if (r < l) r += m;
		cor[i].x = l;
		cor[i].y = r;
		
		sad[i] = l;
		
		arr.pb(cor[i].x);
		arr.pb(cor[i].y);
		
		cor[i + n].x = l + m;
		cor[i + n].y = r + m;
		
		sad[i + n] = l + m;
		
		
		arr.pb(cor[i + n].x);
		arr.pb(cor[i + n].y);
		
		arr.pb(cor[i + n].x + m);
		
		
	}
	
    return FN::solve();
}

int main() {
    if(fopen(task ".inp", "r")) {
        freopen(task ".inp", "r", stdin);
        freopen(task ".out", "w", stdout);
    }
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);

    input();
    
    
    cerr << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << 's' << endl;
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:162:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  162 |         freopen(task ".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:163:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  163 |         freopen(task ".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 14
• Subtask 2: 0 / 17
• Subtask 3: 0 / 9
• Subtask 4: 0 / 13
• Subtask 5: 0 / 21
• Subtask 6: 0 / 26