UVa 138 Street Numbers Solution

#include<iostream>
#include<list>
#include<string>
#include<cstring>
#include<sstream>
#include<cctype>
#include<string.h>
#include<algorithm>
#include<cmath>
#include<stack>
#include<fstream>
#include<cstdlib>
#include<vector>
#include<map>
#include<utility>
#include<iomanip>
#include<queue>
using namespace std;
#define clr(a) memset(a,0,sizeof(a))
#define fill(a,v) memset(a,v,sizeof(a))
#define PB push_back
#define pi acos(-1.0)
#define eps 1e-9


int main()
{
    long long n,x=8,tc=0;
    double n2;
    while(true)
    {
        n2=sqrt((x*x+x)/2);
        n=n2;
        if(n==n2)
        {
            printf("%10lld%10lld\n",n,x);
            tc++;
        }
        if(tc==10)
        break;
        x++;
    }
return 0;
}