无限序列

 1 # include<cstdio>
 2 # include<cstring>
 3 # include<iostream>
 4 # include<algorithm>
 5 using namespace std;
 6 typedef unsigned long long LL;
 7 const int maxn=50000;
 8 const int INF=900000000;
 9 LL f[maxn];
10 int two_find(LL l,LL r,LL x){
11     while(l<r){
12         LL mid=(l+r)>>1;
13         if(f[mid]==x)return 1;
14         else if(f[mid]>x)r=mid;
15         else l=mid+1;
16     }
17     return 0;
18 }
19 int main(){
20     ios::sync_with_stdio(false);
21     LL cur=0,tb=1,num=1,n,x;
22     while(f[cur++]<=INF){
23         f[cur]=num;
24         num=num+tb;
25         tb++;
26     }
27     cin>>n;
28     for(int i=1;i<=n;i++){
29         cin>>x;
30         if(two_find(1,cur,x))printf("1\n");
31         else printf("0\n");
32     }
33     return 0;
34 }