比赛 |
NOIP2023模拟赛4 |
评测结果 |
TTTTTTTTTTTTTTTTTTTT |
题目名称 |
等差子序列 |
最终得分 |
0 |
用户昵称 |
Murasame |
运行时间 |
3.000 s |
代码语言 |
C++ |
内存使用 |
433.13 MiB |
提交时间 |
2023-11-16 12:55:31 |
显示代码纯文本
#include<bits/stdc++.h>
#define mod 1145141919
typedef long long ll;
using namespace std;
struct node{
long long l,r,sum;
}t[2][9000010];
long long tt,n,a[500010];
long long ps[2][500010],md,l1,r1,l2,r2,len,ans,num1,num2;
long long bas[500010];
bool flag;
void build(long long i,long long l,long long r,bool ff){
t[ff][i].l=l;
t[ff][i].r=r;
t[ff][i].sum=0;
if(l==r){
ps[ff][l]=i;
t[ff][i].sum=0;
return;
}
long long mid=(l+r)>>1;
build(i*2,l,mid,ff);
build(i*2+1,mid+1,r,ff);
}
void find(ll i,ll l,ll r,ll ff){
if(l<=t[ff][i].r&&r>=t[ff][i].l){
if(l<=t[ff][i].l&&r>=t[ff][i].r){
ans=(ans+t[ff][i].sum*bas[r-t[ff][i].r])%mod;
return;
}
find(i*2,l,r,ff);
find(i*2+1,l,r,ff);
}
}
void change(ll x,ll ff){
ll now=ps[ff][x];
t[ff][now].sum=1;
while(now/2!=0){
now/=2;
t[ff][now].sum=(t[ff][now*2].sum*bas[t[ff][now*2+1].r-t[ff][now*2+1].l+1]+t[ff][now*2+1].sum)%mod;
}
}
void work(){
memset(t,0,sizeof(t));
memset(a,0,sizeof(a));
memset(ps,0,sizeof(ps));
memset(bas,0,sizeof(bas));
bas[0]=1;
for(int i=1;i<=300005;++i){
bas[i]=bas[i-1]*2%mod;
}
cin>>n;
flag=0;
for(int i=1;i<=n;i++){
cin>>a[i];
}
build(1,1,n,0);
build(1,1,n,1);
for(int i=1;i<=n;i++){
md=a[i];
len=min(a[i]-1,n-a[i]);
l1=a[i]-len;
r1=a[i]+len;
len=2*len+1;
ans=0;
find(1,l1,r1,0);
num1=ans;
r2=n+1-l1;
l2=n+1-r1;
ans=0;
find(1,l2,r2,1);num2=ans;
if(num1!=num2){
flag=1;
break;
}
change(md,0);
change(n-md+1,1);
}
if(flag){
cout<<"Y"<<endl;
}
else{
cout<<"N"<<endl;
}
}
int main(){
freopen("sequence.in","r",stdin);
freopen("sequence.out","w",stdout);
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t;
cin>>t;
for(int i=1;i<=t;i++){
work();
}
return 0;
}