Submission #1751602

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Source Code Expand

#include<bits/stdc++.h>
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define per(i,a,b) for(int i=(a);i>=(b);i--)
#define forE(i,x) for(int i=head[x];i!=-1;i=ne[i])
using namespace std;
typedef long long i64;
typedef unsigned long long u64;
typedef unsigned u32;
typedef pair<int,int> pin;
#define mk(a,b) make_pair(a,b)
#define lowbit(x) ((x)&(-(x)))
#define sqr(a) ((a)*(a))
#define clr(a) (memset((a),0,sizeof(a)))
#define ls ((x)<<1)
#define rs (((x)<<1)|1)
#define mid (((l)+(r))>>1)
#define pb push_back
#define w1 first
#define w2 second
inline void read(int &x){
	x=0;int f=1;char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
	while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
	x*=f;
}
inline void read(i64 &x){
	x=0;int f=1;char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
	while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
	x*=f;
}
inline void judge(){
	freopen("in.txt","r",stdin);
	freopen("out.txt","w",stdout);
}
/*******************************head*******************************/
const int maxn=100005;
const int mod=1e9+7;
int n;
i64 A,B,S[maxn];
struct szsz{
	int sum[maxn];
	inline void add(int x,int v){
		while(x<=n){
			sum[x]=(sum[x]+v)%mod;
			x+=lowbit(x);
		}
	}
	inline int query(int x){
		if(x<0)return 0;
		int res=0;
		while(x){
			res=(res+sum[x])%mod;
			x-=lowbit(x);
		}
		return res;
	}
	inline int query(int l,int r){
		if(l>r)return 0;
		return query(r)-query(l-1);
	}
}F,G;
int f[maxn],g[maxn];
inline int find(int x,int v){
	int l=1,r=x,ans=0;
	while(l<=r){
		int md=(l+r)>>1;
		if(S[x]-S[md]>=v){
			ans=md;l=md+1;
		}else{
			r=md-1;
		}
	}return ans;
}
int main(){
	read(n);read(A);read(B);
	rep(i,1,n)read(S[i]);
	int lstf=0,lstg=0;
	f[1]=1;g[1]=1;
	S[0]=-1e18;
	F.add(1,f[1]);
	G.add(1,g[1]);
	rep(i,2,n){
		int posf=find(i,A),posg=find(i,B);
		//part F
		if(S[i]-S[i-2]>=A)
			f[i]=g[i-1];
		f[i]=(f[i]+G.query(lstf,min(i-2,posf+1)))%mod;

		//part G
		if(S[i]-S[i-2]>=B)
			g[i]=f[i-1];
		g[i]=(g[i]+F.query(lstg,min(i-2,posg+1)))%mod;

		if(S[i]-S[i-1]<B)lstf=i;
		if(S[i]-S[i-1]<A)lstg=i;
		
		F.add(i,f[i]);
		G.add(i,g[i]);
		// printf("%d %d\n",f[i],g[i]);
	}
	bool vf=1,vg=1;
	int ans=0;
	per(i,n,1){
		if(vf){
			ans=(ans+f[i])%mod;
		}
		//if(vf&&S[i+1]-S[i-1]>=A){
		//	ans=(ans+g[i])%mod;
		//}
		if(vg){
			ans=(ans+g[i])%mod;
		}
		//if(vg&&S[i+1]-S[i-1]>=B){
		//	ans=(ans+f[i])%mod;
		//}
		if(S[i]-S[i-1]<A)vf=0;
		if(S[i]-S[i-1]<B)vg=0;
	}
	cout<<ans<<endl;
	return 0;
}

Submission Info

Judge Result