Explain me please, why if n=4, the answer is 204.
I get 2513.

Here is my code:
-----
[The code was here]
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I've got the point. Thank you.

Edited by author 17.07.2011 18:48

/*
    Machine: Class4_B2
    System: Windows7 SP1 32bit
*/
[code deleted]

Edited by moderator 19.11.2019 23:15

what's different between undefined and 3?
can you help me?

I use Tonelli-Shanks algo,but i got WA#2.By now I had read all te topic but hadn't found the error.Please give me some hints or cases.
the key code:

int inverse(int a, int m)//thr inverse element of a(modulo m);
int quickpower(int a, int n, int m)//a^n(modulo m);
void sqrt(int a, int p)
{
    if(p==2)
    {
        cout << 1 << endl;
        return;
    }
    if(quickpower(a,(p-1)/2,p)!=1)
    {
        cout << "No root" << endl;
        return;
    }
    int s, t = 0, b = 0, i, j, x, y, inv, N;
    for (s = p - 1; !(s & 1); s /= 2) t++;
    inv = inverse(a, p);
    x = quickpower(a, (s + 1) / 2, p);
    for (N = 2; quickpower(N, (p - 1) / 2, p) == 1; N++);
    for (i = t - 2; i >= 0; i--)
    {
        b = b ? b*b%p : quickpower(N, s, p);
        y = x*x%p*inv%p;
        for (j = 1; j <= i; j++) y = y*y%p;
        if (y != 1) (x *= b) /= p;
    }
    if (2 * x < p) cout << x << " " << p - x << endl;
    else cout << p - x << " " << x << endl;
    return;
}

Deleting this post... had to hack another solution. Still don't see what was wrong with the original approach... must have been some kind of parsing issue with the input.

Edited by author 08.02.2015 09:36

I am sure that my program is right, but i get WA on test 16.
Do somebody know this test or can say something interesting?

a "for"-loop in python for integers 1 <= i <= 10^18 needs a lot of time. Is there a way to avoid to do such a huge for-loop?


Edited by author 21.01.2015 20:28

hi everybody! i have wa 5 but i don't understand my mistake. can anybody who knows some tests help me?

#include <iostream>

int main()
{
 long int i, n, m, z, s, k, a[16000], l, r, mid;
 std::cin >> n;
 k=0;
 for (i=0; i<n; i++)
 {
  std::cin >> z;
  if ((i!=0) && (z!=a[k]))
  {
   a[k]=z; k++;
  }
  if (i==0)
  {
   a[k]=z; k++;
  }
 }
 n=k-1;
 std::cin >> m;
 s=0;
 k=0;
 for (i=0; i<m; i++)
 {
  l=0; r=n; k=0;
  std::cin >> z;
  if ((z>a[0]) && (z<a[n]))
   while ((l<r) && (k<n-1))
   {
    k=k+1;
    mid=(l+r)/2;
    if (a[mid]>z)
     r=mid;
     else if (a[mid]<z)
     l=mid;
     else if (a[mid]==z)
      break;
   }
  else if ((z==a[0]) || (z==a[n]))
   s++;
  if ((a[mid]==z) && (mid!=0))
   s++;
 }
 std::cout << s;
}

#include<iostream>

using namespace std;

int main()
{
    int k, n, S =0;
    cin >> k >> n;

    if (k, n >= 1 && k, n <= 100) {
        int  *A = (int*)malloc(n*sizeof(int));
        for (int i = 0; i < n; i++) {
            cin >> A[i];
            if (!(A[i] >= 0 && A[i] <= 100))
                break;
        }
        for (int i = 0; i < n; i++)
            S += A[i] - k;
        cout << S << endl;
    }
        return 0;
}

Edited by author 05.02.2015 20:02

Вот мой код. показывает Runtime на 4 тесте. не могу разобраться из-за чего.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication4
{
    class Program
    {
        static void Main()
        {
            bool sol;
            string s = Console.ReadLine();
            string[] sp = s.Split(' ');
            int n = int.Parse(sp[0]);
            int m = int.Parse(sp[1]);
            int q = n + 1;
            int q2 = n + 2;
            int p1, p2, p3;
            int[, ,] mas = new int[q2, q2, q2]; // основной массив для работы.
            for (int i = 0; i < m; ++i)   // заполнение массива с клавиатуры.
            {
                string a = Console.ReadLine();
                string[] b = a.Split(' ');
                int[,] c = new int[1, 3]; // интовый массив вводимой строки

                for (int j = 0; j < 3; ++j)
                {
                    c[0, j] = int.Parse(b[j]);
                    if (j == 2)           // когда массив с заполняется, вынимаем индексы и цены.
                    {
                        p1 = c[0, 0];
                        p2 = c[0, 1];
                        p3 = c[0, 2];
                        mas[p2, p1, 0] = p3; // заполняем 0-ой слой основного массива ценами.
                    }
                }
            }
            for (int i = 1; i <= n; ++i)
            {
                for (int j = 1; j <= n; ++j)
                {
                    sol = true;

                    for (int k = 1; k <= n; ++k)
                    {
                        if (mas[k, i, 0] == 0 & mas[k, j, 0] == 0)
                        {
                            mas[j, i, q] = 0;
                            sol = false;
                        }
                        else
                        {
                            if (mas[k, i, 0] <= mas[k, j, 0] & mas[k, i, 0] != 0)
                            {
                                mas[j, i, k] = mas[k, i, 0];
                            }
                            else
                            {
                                mas[j, i, k] = mas[k, j, 0];
                            }
                            if (mas[j, i, q] < mas[j, i, k])
                            {
                                if (sol) { mas[j, i, q] = mas[j, i, k]; }
                            }
                        }
                    }
                    if (mas[0, 0, 0] == 0)
                    {
                        mas[0, 0, 0] = mas[j, i, q];
                    }
                    else
                    {
                        if (mas[j, i, q] > 0)
                        {
                            if (mas[0, 0, 0] >= mas[j, i, q])
                            {
                                mas[0, 0, 0] = mas[j, i, q];
                            }
                        }
                    }
                }
            }



            if (mas[0, 0, 0] < 1)
            {
                Console.WriteLine("No solution");
            }
            else
            {
                Console.WriteLine(mas[0, 0, 0]);
            }
            Console.ReadKey();
        }
    }
}

any hints???

Если изменить правило 2(если n делится на k) и вместо k умножить на 1, то все заработает.

Определение 1. n!!…! = n(n−k)(n−2k)…(n mod k), если n не делится на k; n!!…! = n(n−k)(n−2k)…1, если n делится на k (знаков ! в обоих случаях k штук).

Если что-то не получается, пишите вк: https://vk.com/evgeniy_baskov.
Разберемся:)

who knows what the meaning of set of numbers is???
is it true that the user must specify how many numbers must be taken?

Edited by author 03.02.2015 23:09

Здравствуйте,
У меня возникают постоянные ошибки при сдаче программ на Py2.7, например задача: 1293

N = input()
B = input()
A = input()
print 2*N*A*B

Выдает RE.

Тот же код на Pascal сдается:
var
A, N, B: integer;
begin
read(N, A, B);
write(2*N*B*A);
end.

И это только единичный случай, так со всеми. Я даже не могу задачку a + b решить =\

in.nextToken();
        int n = (int) in.nval;
        byte ch1[] = new byte[n];
        byte ch2[] = new byte[n];
        while (n > 0) {
            in.nextToken();
            ch1[n - 1] = (byte) in.nval;
            in.nextToken();
            ch2[n - 1] = (byte) in.nval;
            n--;
        }
        int ost = 0;
        String answer = "";
        for (int i = 0; i < ch1.length; i++) {
            int a = ost + ch1[i] + ch2[i];
            if (a > 9) {
                answer = (a % 10) + answer;
                ost = a / 10;
            } else {
                answer = a + answer;
                ost = 0;
            }
        }
        out.print(answer);

Edited by author 02.02.2015 20:11