Competitive/Collaborative Programming Class

/*
 * =====================================================================================
 *
 *       Filename:  11866.cpp
 *
 *    Description:  Problem 11866 - Triangle
 *
 *        Version:  1.0
 *        Created:  10/05/2011 06:19:53 PM
 *       Revision:  none
 *       Compiler:  g++
 *
 *         Author:  Andrew Stewart 
 *        Company:  
 *
 * =====================================================================================
 */
#include <iostream>

using namespace std;
unsigned long long num2(int n) {
  unsigned long long x=1;
  if (n%3 == 1) {
    x*=(n+2)/3;
    if (n%2) {
      x*=((n+1)/2);
      x*=n;
    } else {
      x*=(n/2);
      x*=(n+1);
    }
    return x;
  }
  else if (n%3 == 2) {
    if (n%2) {
      x*=( (n+1)/6);
      x*=(n);
      x*=(n+2);
      return x;
    }
    x*=((n+1)/3);
    x*=(n/2);
    x*=(n+2);;
    return x;
  }
  else {
    x*= (n/3);
    if (n%2) {
      x*=((n+1)/2);
      x*=(n+2);
    }
    else {
      x*=((n+2)/2);
      x*=(n+1);
    }
    return x;
  }
}

unsigned long long num4(int n) {
  unsigned long long x = num2(n);
  unsigned long long y = 1;
  if (n%3==1) {
    y *= ((n-1)/3);
    if (n%2) {
      y *= ((n+1)/2);
      y *= n;
    } else {
      y *= (n/2);
      y*= (n+1);
    }
  } else if (n%3==2) {
    y *= ((n+1)/3);
    if (n%2) {
      y*= ((n-1)/2);
      y*=n;
    } else {
      y*= (n/2);
      y*= (n-1);
    }
  } else {
    if (n%2) {
      y*= (n/3);
      y*= ((n-1)/2);
      y*= (n+1);
    } else {
      y*= (n/6);
      y*= (n-1);
      y*= (n+1);
    }
  } 
  return x+y;
}

unsigned long long num5(int n) {
  unsigned long long x = n;
  x*=(n+1);
  x/=2;
  return x;
}

unsigned long long num6(int n) {
 unsigned long long x = num4(n/2);
  x += num4(n/2);
  x -= num5(n/2);
  if (n%2) { unsigned long long m = n; m*=n; m/=4; x += m;}
  return x;
}

unsigned long long num7(int n, int m) {
  return num6(m)-num6(2*n-1);
}

unsigned long long num3(unsigned long long n, unsigned long long int m) {
  if (m<2*n) return 0;
  unsigned long long y = m*n*n;
  unsigned long long x = (m*m*n-m*m-3*m+5*m*n)/2;
  y += num7(n,m);
  y += 2*n*n+1;
  y += -3*n;
  y -= x;
  return y;
}


unsigned long long num(int n,int m) {
  unsigned long long x = num2(m-n+1);
  unsigned long long y = num3(n,m);
  return x-y;
}

int main()
{
  int x,y,n;
  cin >> n;
  while (n-->0)
  {
    cin >> x >> y;
    cout << num(x,y) << endl;
  }
}

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