CareerCup

what kind of numbers, real/integer

int add_Num(int arr[], int n ){
  
  int sum = 0;
  int j = 0;
  while (j < n ){
    sum+=arr[j];
    j++;
  }
 return sum;
}

The obvious solution require O(n) operations. While the following one require O(lgn) operations. It may be the reason they asked the question.

int Sum(int A[], int h, int l)
{
  if (h==l) return A[l];
  else
  {
     int m=l+(h-l)/2;
      return Sum(A,l,m-1)+Sum(A,m+1,h);		
  }
	
}

yahoo asks such trivial questions ??

Write a template function?

template <class T>
T sum(T* arr, int num){
T sum=0;
for(int i=0;i<num;i++){
sum += arr[i];
}
return sum;
}

/* program to add two numbers. each number is represented by an int array. 
 * each element in the array is an number */ 

#include <iostream>
using namespace std; 

void PrintNumber(int* array, int len)
{
	for( int i = 0; i<len; i++ )
		cout << array[i]; 
	cout << endl;
}

void reverse_array(int* array, int len)
{
	int* p = array; 
	int* q = p + (len-1); 
	int temp; 
	while( p < q )
	{
		temp = *p; 
		*p = *q; 
		*q = temp; 
		p++; 
		q--; 
	}
}

void AddNumbers(int* array1, int len1, int* array2, int len2, int** array3, int* len3)
{
	int max_len = max(len1, len2); 
	int* sum_array = (int*)malloc(sizeof(int) * (max_len+1)); //+1 for carry
   	
	int i, j;  
	int k = 0;
	int carry = 0; 
	for( i = len1-1, j = len2-1; i >= 0 && j >=0; i--, j--, k++ )
	{
		if( (array1[i] + array2[j] + carry) > 9 )
		{
			sum_array[k] = (array1[i] + array2[j] + carry) % 10; 
			carry = 1; 
		}
		else
		{
			sum_array[k] = array1[i] + array2[j] + carry; 
			carry = 0; 
		}
	}	

	if( i > 0 )
	{
		for( ; i >= 0; i--, k++ )
		{
			if( (array1[i] + carry) > 9 )
			{
				sum_array[k] = (array1[i] + carry)%10; 
				carry = 1; 
			}
			else
			{
				sum_array[k] = array1[i] + carry; 
				carry = 0; 
			}
		}
	}
	else if( j > 0 )
	{
		for( ; j >= 0; j--, k++ )
		{
			if( (array2[j] + carry) > 9 )
			{
				sum_array[k] = (array2[j] + carry)%10; 
				carry = 1; 
			}
			else
			{
				sum_array[k] = array2[j] + carry; 
				carry = 0; 
			}
		}
	}

	sum_array[k] = carry; 

	reverse_array(sum_array, max_len+1); 
	*array3 = sum_array; 
	*len3 = max_len+1;
}


int main()
{
	int array1[] = { 1, 1, 1, 1 }; 
	int array2[] = { 9, 9 }; 

	PrintNumber(array1,sizeof(array1)/sizeof(array1[0])); 
	PrintNumber(array2,sizeof(array2)/sizeof(array2[0])); 

	int* array3 = NULL; 
	int len = 0; 
	AddNumbers(array1, sizeof(array1)/sizeof(array1[0]), array2, sizeof(array2)/sizeof(array2[0]), &array3, &len); 
	cout << "done with adding numbers" << endl;
	PrintNumber(array3,len); 
	
	return 0; 
}

May be they are looking for this

(defun sum-list (list)
  (if list
      (+ (car list) (sum-list (cdr list)))
    0))