ll partition(ll *a,ll s,ll e)
{
ll i=s-1;
ll j=s;
ll pivot=a[e];
for(;j<=e-1;j++)
{
if(a[j]<=pivot)
{
i++;
swap(a[i],a[j]);
}
}
swap(a[i+1],a[j]);
return i+1;
}
in partition loop why we run loop from j=s to e-1 and not e?
what will be the problem if we run j<=e instead of j<=e-1.
Thank you.
hello @dhruvilcodes
a[e] is the pivot element itself.
when the loop will over then value of j will be e.
so this line is nothing but swap(a[i+1],a[e]) which is correct . we want to do exaclty same thing.
if u will iterate till j=e then there is no need of external swap function.
check this implementation for clarity->
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