Please, help me. My code:
#include <iostream>
#include <cstring>
#include <cctype>

using namespace std;

const int MaxSourceSize = 100000;
const int MaxBuffSize = 1000;
const int nKeyWord = 36;

const char *comment_start = "<span class=comment>";
const char *keyword_start = "<span class=keyword>";
const char *string_start = "<span class=string>";
const char *number_start = "<span class=number>";
const char *end_teg = "</span>";

const char KeyWords[nKeyWord][sizeof( "implementation" )] = {
                          "and", "array", "begin",
                                 "case", "class", "const",
                          "div", "do", "else",
                          "end", "for", "function",
                          "if", "implementation", "interface",
                          "mod", "not", "of",
                          "or", "procedure", "program",
                          "record", "repeat", "shl",
                          "shr", "string", "then",
                          "to", "type", "unit",
                          "until", "uses", "var",
                          "with", "while" };
int main()
{
    register int i, j, g;
    char source[MaxSourceSize];
    cin.get ( source, MaxSourceSize, 0 );
    cin.ignore();
    for ( i = 0; source[i]; i++ )
    {
        if ( isalpha ( source[i] ) || source[i] == '_' )
        {
            char buff[MaxBuffSize];
            bool itKeyWord = false;
            for ( g = i, j = 0; isalnum ( source[g] ) || source[g] == '_'; g++, j++ )
                buff[j] = tolower ( source[g] );
            buff[j] = 0;
            for ( j = 0; j < nKeyWord; j++ )
                if ( !strcmp ( buff, KeyWords[j] ) )
                {
                    itKeyWord = true;
                    break;
                }
            if ( itKeyWord ) cout << keyword_start;
            for ( i; isalnum ( source[i] ) || source[i] == '_'; i++ )
                cout << source[i];
            i--;
            if ( itKeyWord ) cout << end_teg;
        }
        else
        {
            if ( isdigit ( source[i] ) )
            {
                cout << number_start;
                for ( i; isdigit ( source[i] ) || ( source[i] == '.' && source[i+1] != '.' ); i++ )
                    cout << source[i];
                i--;
                cout << end_teg;
            }
            else
            {
                switch ( source[i] )
                {
                    case '{':
                        {
                            int in = 0;
                            cout << comment_start;
                            for ( ; ; i++ )
                            {
                                if ( source[i] == '{' ) in++;
                                else if ( source[i] == '}' )
                                {
                                    in--;
                                    if ( !in )    {cout << source[i];break;}
                                }
                                cout << source[i];
                            }
                            cout << end_teg;
                            //i--;
                        };break;
                    case '\\':
                        {
                            if ( source[i+1] == '\\' )
                            {
                                cout << comment_start;
                                for ( i; source[i] != '\n'; i++ )
                                    cout << source[i];
                                cout << end_teg;
                                i--;
                            }
                            else
                            {
                                cout << '\\';
                            }
                        };break;
                    case '\'':
                        {
                            cout << string_start;
                            cout << source[i++];
                            for ( i; source[i] != '\''; i++ )
                                cout << source[i];
                            cout << source[i];
                            cout << end_teg;
                        };break;
                    case '#':
                        {
                            cout << string_start;
                            i++;
                            cout << "#";
                            for ( i; isdigit ( source[i] ) || ( source[i] == '.' && isdigit ( source[i+1] ) ); i++ )
                                cout << source[i];
                            cout << end_teg;
                            i--;
                        };break;
                    default:
                        {
                            cout << source[i];
                        };break;
                }
            }
        }
    }
    return NULL;
}

I cann't understand why WA#10. Must I use long double? Please, give me some terrible tests.

using System;

public class Sum
{
    private static void Main()
    {
        string[] tokens = Console.ReadLine().Split(' ');
        Console.WriteLine(int.Parse(tokens[0]) + int.Parse(tokens[1]));
    }
}

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

namespace T1
{
    class Program
    {
        static void Main(string[] args)
        {

            //List<int> n = new List<int>();

            List<long> ans = new List<long>();

            long s = System.Int64.Parse(Console.ReadLine());

            for (int i = 0; i < s; i++)
            {
                int x = int.Parse(Console.ReadLine());
                ans.Add(Find(x));
            }

            for (int i = 0; i < s; i++)
            {
                Console.Write(ans[i]);
                Console.Write(" ");
            }



            //Console.ReadKey();
        }

        static long Find(long x)
        {

            // (a)n^2 + (b)n - (c)2x = 0
            // a = 1
            // b = 1
            // c = 2 * x

            double a = 1, b = 1, c = - 2 * x + 2;
            double d = b * b - 4 * a * c;
            double p = (-b + Math.Sqrt(d)) / 2 * a;

            return (p - (long) p) > 0 ? 0 : 1;

        }
    }
}

using System;
using System.Linq;
using System.Text;

namespace Sum
{
    class Program
    {
        static void Main(string[] args)
        {
            int x, p = 0;
            x = int.Parse(Console.ReadLine());

            if (x < 0 && x >= -10000)
            {
                for (int i = x; i <= 1; i++)
                    p += i;
            }
            else if (x > 0 && x <= 10000)
            {
                for (int i = 1; i <= x; i++)
                    p += i;
            }
            else
                p = 1;

            Console.WriteLine(p);

            //Console.ReadKey();
        }
    }
}

using System;
using System.Linq;
using System.Text;

namespace Bicycle_Codes
{
    class Program
    {
        static void Main(string[] args)
        {
            int c1 = int.Parse(Console.ReadLine());
            int c2 = int.Parse(Console.ReadLine());
            if (c1 % 2 == 0 || c2 % 2 != 0)
                Console.WriteLine("yes");
            else if (c1 % 2 != 0 || c2 % 2 == 0)
                Console.WriteLine("no");

            //Console.ReadKey();
        }
    }
}

It is interesting to me is that problem can be solved by
max flow algorithm of Ford-Falkerson, or we must use another max flow algorithm?

#!/usr/local/bin/ruby -w

f, s = gets.split(" ").map(&:to_i)

if f%2==0 || s%2!=0
  puts   "yes"
else
  puts  "no"
end



What is wrong?

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

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {

            Console.WriteLine("vvedit a");
            int a = int.Parse(Console.ReadLine());
           if((1<=a)&&(a<=4)) Console.WriteLine("few") ;
      else if((5<=a)&&(a<=9)) Console.WriteLine("several");
           else if ((10 <= a) && (a <= 19)) Console.WriteLine("pack");
           else if ((20 <= a) && (a <= 49)) Console.WriteLine("lots");
           else if ((50 <= a) && (a <= 99)) Console.WriteLine("horde");
           else if ((100 <= a) && (a <= 249)) Console.WriteLine("throng");
           else if ((250 <= a) && (a <= 499)) Console.WriteLine("swarm");
           else if ((500 <= a) && (a <= 999)) Console.WriteLine("zounds");
           else if ((1000 <= a) && (a <= 2000)) Console.WriteLine("legion");


           }
        }
    }

I used C++11 with long long type, still cannot pass #15. After changing my code to python 2.7, I got the AC. Since the input range is [-2000000000,2000000000], long long type should not suffer from overflow. Then what's the reason of WA 15?

uses crt;
var
s:string;
a,k:longint;

begin
read(a);
        k:=9;
        repeat
        if a mod k=0 then
         begin
         s:=chr(k+48)+s;
         a:=a div k;
         end
        else
        k:=k-1;
        until k=1;
        if a=1 then
         begin
         write(s);
         end
        else write('-1');

end.

Edited by author 13.05.2014 06:59

Edited by author 13.05.2014 07:22

Edited by author 13.05.2014 07:23

if n=1(k any) we need 2 minuten, but when n=2 , k=5 we need 1 minutes. Why???

i found the bug

Edited by author 13.05.2014 22:15

Any ideas, what's wrong? (I used greedy alogorithm)

WereWolf can eat his sister or brother.
But He cannot eat his father and mother, also grandfather ... so on....grandmother...

Sample
5 4
4 1 4 1 2
Why answer is 3 2 but not 3 1 ?
2*1+1*2 <= 4
(p = 4, p — максимальная сила всплеска, которую маги ещё могут пережить, пережить тоесть включно) ???

I strongly dislike being forced to specific languages. Java is too slow to solve the problem? OK. Why ban it?

var
n:integer;

begin
while not seekeof do
      begin
       read(n);
       write(sqrt(n):0:4);

      end;
end.

Wrong answer, but why???