My practice dump of https://www.coursera.org/learn/algorithms-part1

| quick-find | M x N | M = # of union-find operations, N = # of elements |
| quick-union (QU) | M x N | |
| weighted QU (WQU) | N + M x logN | |
| path-compressed(PC) QU | N + M x logN | |
| PC-WQU | N + M x logN | log = # of times logN needs to be taken to reach the value 1 |
| Improved-PCWQU | N + M x f(M,N) | f is the Ackermann function | |