Prefix Array
This is really simple, though I just did forget how to code one up.
ll prefix_sum(int l, int r) {
if (l == 0) {
return prefix[r];
} else {
return prefix[r] - prefix[l-1];
}
}
// load in to array
for (int i=0;i<n;i++) {
cin >> prefix[i];
}
for (int i=1;i<n;i++) {
prefix[i] += prefix[i-1];
}Parallelized Prefix Sum
Learned this through PMPP. Didn’t know it was possible, because it seems like sequential.
