Longest common substring

Longest common substring

int f(int* a, int* b, int n)
{
int arr[n][n];
int max=0;
for(int i=0;i<n;i++)
for(int j=0;j<n;j++)
{
if(i==0)//first row
{
if(a[i]==b[j]) {arr[i][j]=1; if(max<arr[i][j]) max=arr[i][j];}
else arr[i][j]=0;
}
else if(j==0)//first col
{
if(a[i]==b[j]) {arr[i][j]=1; if(max<arr[i][j]) max=arr[i][j];}
else arr[i][j]=0;
}
else 
{
if(a[i]==b[j]) {arr[i][j]=arr[i-1][j-1]+1; if(max<arr[i][j]) max=arr[i][j];}
else arr[i][j]=0;
}
}
return max;
}