> [...] what N must count. Traditionally, it counts comparisons, swaps, or other algorithmic events. Er, N is counting the input elements (eg number of nodes i

> [...] what N must count. Traditionally, it counts comparisons, swaps, or other algorithmic events. Er, N is counting the input elements (eg number of nodes in a graph, array length, etc), O() is what counts algorithmic or microarchitectural events. > Similarly, "if (c) a -= b;" may become "a -= (-c & b);". Reminds me of speeding up a ECC loop by almost two orders of magnitude with (basically): - if(i&(1<<k)) p ^= parity(x[i])<<k; + p32[k] ^= x[i] & -(ii&1); ii>>=1;