为什么找不到此HashSet的Sum（）。 说：“算术运算导致溢出。”

Question

I was trying to solve this problem projecteuler,problem125

this is my solution in python(just for understanding the logic)

lim = 10**8
total=0
found= set([])
for start in xrange(1,int(lim**0.5)):
    s=start**2
    for i in xrange(start+1,int(lim**0.5)):
        s += i**2
        if s>lim:
            break
        if str(s) == str(s)[::-1]:
            found.add(s)

print sum(found)

the same code I wrote in C# is as follows

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        public static bool isPalindrome(string s)
        {
            string temp = "";
            for (int i=s.Length-1;i>=0;i-=1){temp+=s[i];}
            return (temp == s);
        }
        static void Main(string[] args)
        {
            int lim = Convert.ToInt32(Math.Pow(10,8));
            var found = new HashSet<int>();
            for (int start = 1; start < Math.Sqrt(lim); start += 1)
            {
                int s = start *start;
                for (int i = start + 1; start < Math.Sqrt(lim); i += 1)
                {
                    s += i * i;
                    if (s > lim) { break; }
                    if (isPalindrome(s.ToString())) 
                    { found.Add(s); }
                }
            }
            Console.WriteLine(found.Sum());

        }
    }
}

the code debugs fine until it gives an exception at Console.WriteLine(found.Sum()); (line31). Why can't I find Sum() of the set found

Answer 1

The sum is: 2,906,969,179.

That is 759,485,532 greater than int.MaxValue;

Change int to long in var found = new HashSet<long>(); To handle the value.

You can also use uint however instead of long , however I would recommend using long .