Day 3

Today I have Learned about Space Complexity.

What is space complexity?

Total amount of memory space used by an algorithm/program including the space of input values for execution.

Space Complexity = Auxilary space + Space use by input values 

In space complexity A good Algorithm keeps space complexity as low as possible.

Examples:

int sum(int x, int y, int z)
{
int t = x+y+z;
return t;
}

Time complexity is order of 1 o(1).


5 variables - x,y,z,t,1

we need two bytes for all varibales so:
2+2+2+2+2=10;

and 

if their is constant variable there is order of 1 o(1)

If there is constant then the space and time complexity is big O of 1 o(1) . 

Example 2:

int sum(int a[], int n)
{
int r=0;
for(int i = 0; i<n;++i)
{
r+=a[i];
}
return r;
}

In this sum our variables are 
1.a[]=2n
2.n=2
3.r=2
4.i=2
5.return r=2

here 2+2+2+2= 8

means 

8+2n = means our space complexity will be big o of n o(n)

when we use array in that case our constant space complexity is not required

What is the concept here ?

Just chek the variables and see the space complexuty for that.

Example 3:

void matrixAdd(int a[]),int b[], int c[],int n)
{
for(int i=0;i<n;++i)
{
c[i]=a[i]+b[j];
}
}

i,n,c,a,b,j
a[]
b[]
c[]
i
n

6n+4

total space complexity = o(n)

the concept is simple if their is array then the value is big o of n O(n)  
and if its constant then it's O(1).

I have also  saw some more examples on geeks for geeks.

I have learned this from the video of computer shastra space complexity.