runtah: UVa 10830 A New Function

Saturday, September 3, 2016

UVa 10830 A New Function

#include <set>
#include <map>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <cctype>
#include <cstdio>
#include <string>
#include <vector>
#include <cassert>
#include <cstdlib>
#include <cstring>
#include <sstream>
#include <iostream>
#include <algorithm>

typedef unsigned long long ull;
typedef long long xll;
typedef long double ld;

using namespace std;
ull sumfind(ull a, ull n)
{
 return ((n*(n+1)/2) - (a*(a-1)/2));
}
ull csod(ull n)
{
 ull root = (ull)sqrt((double)n), i, j;
 ull lim, sum=0;

 for (i=2 ; i<=root ; i++)
 {
 lim = n/i;
 sum += (sumfind(i+1,lim) + (i*(lim-i+1)));
 }

 return sum;
}

int main()
{
 ull n, sum=0, kase=1;

 while (cin >> n && n)
 {
 cout << "Case " << kase++ << ": " << csod(n) << endl;
 }
 return 0;

}

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