Submission #409566

#	Time	Username	Problem	Language	Result	Execution time	Memory
409566		jeqcho	Boat (APIO16_boat)	C++17	31 / 100	2113 ms	270600 KiB

boat

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

typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<pair<int,int>> vpi;

#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define trav(a,x) for (auto& a: x)

#define pb push_back
#define rsz resize
#define sz(x) int(x.size())
#define all(x) begin(x), end(x)
#define fi first
#define se second

int const N=5e2+3;
int a[N],b[N];
int const D=1e6+3;
ll dp[D];
ll mod =1e9+7;

int main()
{
	ios_base::sync_with_stdio(0); cin.tie(0);
	int n;
	cin>>n;
	set<int> st;
	F0R(i,n)
	{
		cin>>a[i]>>b[i];
		FOR(j,a[i],b[i]+1)
		{
			st.insert(j);
		}
	}
	vi v(all(st));
	map<int,int>mp;
	F0R(i,sz(st))
	{
		mp[v[i]]=i+1;
	}
	F0R(i,n)
	{
		a[i]=mp[a[i]];
		b[i]=mp[b[i]];
	}
	F0R(j,sz(st)+1)
	{
		dp[j]=0;
	}
	dp[0]=1;
	F0R(i,n)
	{
		ll sum=0;
		F0R(j,b[i]+1)
		{
			ll temp = dp[j];
			if(j>=a[i])
			{
				dp[j]+=sum;
				dp[j]%=mod;
			}
			sum += temp;
			sum%=mod;
		}
	}
	ll ans=0;
	FOR(j,1,sz(st)+1)
	{
		ans+=dp[j];
		ans%=mod;
	}
	cout<<ans<<'\n';
	return 0;
}

• Subtask 1: 9 / 9
• Subtask 2: 22 / 22
• Subtask 3: 0 / 27
• Subtask 4: 0 / 42