Partition

ℹ️ What is a partition?
A partition of a set is a decomposition of a set into subsets such that each element of the set is precisely in one subset. The subsets are defined in C++ by a unary predicate so that the members of the first subset fulfill the predicate. The remaining elements are in the second subset.

C++ offers a few functions for dealing with partitions. All of them need a unary predicate pre. std::partition and std::stable_partition take as input a predicate and a range and partition it according to the predicate and return the partition point. With std::partition_point we can get the partition point of a partition. Afterwards we can check the partition with std::is_partitioned or copy it with std::partition_copy.

std::is_partitioned: Checks if the range is partitioned.