#581877 (C++14) No.1294 マウンテン数列

• 問題: No.1294 マウンテン数列
• ユーザー: kotatsugame
• 提出日時: 2020-11-20 22:05:05
• 言語: C++14 (gcc 12.3.0 + boost 1.83.0)
• 結果: AC
• 実行時間: 243 ms / 2,000 ms
• コード長: 2,705 bytes
• コンパイル時間: 915 ms
• コンパイル使用メモリ: 69,876 KB
• 実行使用メモリ: 6,944 KB
• 最終ジャッジ日時: 2024-07-23 13:04:11
• 合計ジャッジ時間: 3,054 ms
• ジャッジサーバーID （参考情報）: judge1 / judge2

入力	結果	実行時間; 実行使用メモリ
testcase_00	AC	2 ms; 6,812 KB
testcase_01	AC	2 ms; 6,940 KB
testcase_02	AC	2 ms; 6,940 KB
testcase_03	AC	2 ms; 6,940 KB
testcase_04	AC	2 ms; 6,944 KB
testcase_05	AC	19 ms; 6,940 KB
testcase_06	AC	27 ms; 6,940 KB
testcase_07	AC	2 ms; 6,944 KB
testcase_08	AC	2 ms; 6,940 KB
testcase_09	AC	2 ms; 6,944 KB
testcase_10	AC	243 ms; 6,940 KB
testcase_11	AC	242 ms; 6,944 KB
testcase_12	AC	241 ms; 6,944 KB
testcase_13	AC	236 ms; 6,940 KB
testcase_14	AC	197 ms; 6,944 KB
testcase_15	AC	227 ms; 6,940 KB
testcase_16	AC	199 ms; 6,944 KB

コンパイルメッセージ

a.cpp:24:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]

ソースコード

#line 1 "a.cpp"
#include<iostream>
#include<algorithm>
using namespace std;
#line 3 "/home/kotatsugame/library/math/modint.cpp"
#include<utility>
template<int m>
struct modint{
	unsigned int x;
	constexpr modint()noexcept:x(){}
	template<typename T>
	constexpr modint(T x_)noexcept:x((x_%=m)<0?x_+m:x_){}
	constexpr unsigned int val()const noexcept{return x;}
	constexpr modint&operator++()noexcept{if(++x==m)x=0;return*this;}
	constexpr modint&operator--()noexcept{if(x==0)x=m;--x;return*this;}
	constexpr modint operator++(int)noexcept{modint res=*this;++*this;return res;}
	constexpr modint operator--(int)noexcept{modint res=*this;--*this;return res;}
	constexpr modint&operator+=(const modint&a)noexcept{x+=a.x;if(x>=m)x-=m;return*this;}
	constexpr modint&operator-=(const modint&a)noexcept{if(x<a.x)x+=m;x-=a.x;return*this;}
	constexpr modint&operator*=(const modint&a)noexcept{x=(unsigned long long)x*a.x%m;return*this;}
	constexpr modint&operator/=(const modint&a)noexcept{return*this*=a.inv();}
	constexpr modint operator+()const noexcept{return*this;}
	constexpr modint operator-()const noexcept{return modint()-*this;}
	constexpr modint pow(long long n)const noexcept
	{
		if(n<0)return pow(-n).inv();
		modint x=*this,r=1;
		for(;n;x*=x,n>>=1)if(n&1)r*=x;
		return r;
	}
	constexpr modint inv()const noexcept
	{
		int s=x,t=m,x=1,u=0;
		while(t)
		{
			int k=s/t;
			s-=k*t;
			swap(s,t);
			x-=k*u;
			swap(x,u);
		}
		return modint(x);
	}
	friend constexpr modint operator+(const modint&a,const modint&b){return modint(a)+=b;}
	friend constexpr modint operator-(const modint&a,const modint&b){return modint(a)-=b;}
	friend constexpr modint operator*(const modint&a,const modint&b){return modint(a)*=b;}
	friend constexpr modint operator/(const modint&a,const modint&b){return modint(a)/=b;}
	friend constexpr bool operator==(const modint&a,const modint&b){return a.x==b.x;}
	friend constexpr bool operator!=(const modint&a,const modint&b){return a.x!=b.x;}
	friend ostream&operator<<(ostream&os,const modint&a){return os<<a.x;}
	friend istream&operator>>(istream&is,modint&a){long long v;is>>v;a=modint(v);return is;}
};
#line 5 "a.cpp"
using mint=modint<998244353>;
int N,A[2525];
mint dp[2525];
mint cumsum[2525];
mint calc(int K)
{
	for(int i=1;i<N;i++)if(A[i]-A[i-1]>=K)return 0;
	for(int i=1;i<=N;i++)dp[i]=1;
	for(int i=0;i<=N;i++)cumsum[i]=0;
	for(int i=1;i<N;i++)
	{
		dp[i]+=cumsum[i];
		int j=lower_bound(A,A+N,A[i-1]+K)-A;
		cumsum[i+1]+=dp[i];
		cumsum[j]-=dp[i];
		cumsum[i+1]+=cumsum[i];
	}
	return dp[N-1]*2;
}
main()
{
	cin>>N;
	for(int i=0;i<N;i++)cin>>A[i];
	mint fac=mint(2).pow(N-1);
	mint ans=0;
	for(int K=1;K<=2500;K++)
	{
		ans+=(fac-calc(K));
	}
	cout<<ans<<endl;
}