Algorithms and review papers
Any verbatim copying of a long block of text, including if that block of text is an algorithm, would be plagiarism if it is not attributed. However, you can avoid plagiarism by stating explicitly that your description of the algorithm is copied verbatim from another source, and citing the source. Then you cannot be accused of plagiarism, although it may still be considered poor or lazy writing if a substantial amount of your review is copied from other sources.