HDU 1719 Friend 打表

#include<iostream>#include<vector>#include<algorithm>using namespace std;vector<int> v;int main(){    v.push_back(1);v.push_back(2);    for(int i=0;i<v.size();i++){        if(v.size()>1000) break;        v.push_back((v[i]+1)*(v[i]+1)-1);        int k=(int)v.size();        for(int j=i+1;j<k;j++){            v.push_back((v[i]+1)*(v[j]+1)-1);        }    }    sort(v.begin(),v.end());    vector<int>::iterator new_end=(unique(v.begin(),v.end()));    int n;    while(scanf("%d",&n)!=EOF)    {        vector<int>::iterator it=lower_bound(v.begin(),new_end,n);        if(*it!=n) cout<<"NO!"<<endl;        else cout<<"YES!"<<endl;    }    return 0;}