Submission #20466

#	Time	Username	Problem	Language	Result	Execution time	Memory
20466		책상다리황새두렁넘기 (#35)	초음속철도 (OJUZ11_rail)	C++11	45 / 100	9 ms	18552 KiB

rail

#include<bits/stdc++.h>
#define X first
#define Y second
using namespace std;
typedef long long ll;
const ll mod = 1e9+7;

ll m, n, two[100005], sz;
pair<ll,ll> a[100005];
vector<ll> cpr;

struct segtree {
	ll val[888888], lazy[888888];
	void lazydown (ll P) {
		val[2*P] = (val[2*P] * two[lazy[P]]) % mod;
		lazy[2*P] += lazy[P];
		val[2*P+1] = (val[2*P+1] * two[lazy[P]]) % mod;
		lazy[2*P+1] += lazy[P];
		lazy[P] = 0;
	}
	void pl (ll SS, ll SE, ll X, ll P, ll V) {
		if(SE < X || X < SS) return;
		if(SS == SE) {val[P] += V; return;}
		lazydown(P);
		ll mid = (SS+SE)/2;
		pl(SS, mid, X, 2*P, V);
		pl(mid+1, SE, X, 2*P+1, V);
		val[P] = (val[2*P] + val[2*P+1]) % mod;
	}
	void pl(ll X, ll V) {pl(0, sz-1, X, 1, V);}
	void ml (ll SS, ll SE, ll S, ll E, ll P, ll V) {
		if(S <= SS && SE <= E) {
			val[P] = (val[P] * two[V]) % mod;
			lazy[P] += V;
			return;
		}
		if(SE < S || E < SS) return;
		lazydown(P);
		ll mid = (SS+SE)/2;
		ml(SS, mid, S, E, 2*P, V);
		ml(mid+1, SE, S, E, 2*P+1, V);
		val[P] = (val[2*P] + val[2*P+1]) % mod;
	}
	void ml (ll S, ll E, ll V) {ml(0, sz-1, S, E, 1, V);}
	ll query (ll SS, ll SE, ll S, ll E, ll P) {
		if(S <= SS && SE <= E) return val[P];
		if(SE < S || E < SS) return 0;
		lazydown(P);
		ll mid = (SS+SE)/2;
		return (query(SS, mid, S, E, 2*P) +
				query(mid+1, SE, S, E, 2*P+1)) % mod;
	}
	ll query (ll S, ll E) {return query(0, sz-1, S, E, 1);}
} seg;

int main()
{
	scanf("%lld%lld",&m,&n);
	two[0] = 1;
	for(int i=1;i<=n;i++) {
		two[i] = (two[i-1] * 2) % mod;
	}
	for(int i=1;i<=n;i++) {
		scanf("%lld%lld",&a[i].X,&a[i].Y);
		cpr.push_back(a[i].X);
		cpr.push_back(a[i].Y);
	}
	sort(cpr.begin(), cpr.end());
	cpr.erase(unique(cpr.begin(), cpr.end()), cpr.end());
	if(cpr[0] != 1 || cpr.back() != m) {puts("0"); return 0;}
	for(int i=1;i<=n;i++) {
		a[i].X = lower_bound(cpr.begin(), cpr.end(), a[i].X) - cpr.begin();
		a[i].Y = lower_bound(cpr.begin(), cpr.end(), a[i].Y) - cpr.begin();
	}
	sort(a+1, a+1+n);
	sz = cpr.size();
	seg.pl(0, 1);
	for(int i=1;i<=n;i++) {
		seg.pl(a[i].Y, seg.query(a[i].X, a[i].Y));
		seg.ml(a[i].Y+1, sz-1, 1);
	}
	printf("%lld\n",seg.query(sz-1, sz-1));
}

Compilation message (stderr)

rail.cpp: In function 'int main()':
rail.cpp:58:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%lld%lld",&m,&n);
                         ^
rail.cpp:64:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lld%lld",&a[i].X,&a[i].Y);
                                    ^

• Subtask 1: 10 / 10
• Subtask 2: 8 / 8
• Subtask 3: 0 / 25
• Subtask 4: 27 / 27
• Subtask 5: 0 / 30