### 7 releases (4 stable)

Uses old Rust 2015

1.0.3 | Mar 27, 2017 |
---|---|

1.0.2 | Mar 24, 2017 |

0.1.2 | Feb 11, 2017 |

0.1.1 | Feb 3, 2017 |

0.1.0 | Jan 26, 2017 |

#**587** in Algorithms

**1,084** downloads per month

**Apache-2.0/MIT**

33KB

517 lines

# Pattern-defeating quicksort

This sort is significantly faster than the standard sort in Rust. In particular, it sorts random arrays of integers approximately 45% faster. The key drawback is that it is an unstable sort (i.e. may reorder equal elements). However, in most cases stability doesn't matter anyway.

The algorithm is based on pdqsort by Orson Peters, published at: https://github.com/orlp/pdqsort

#### Now in nightly Rust

If you're using nightly Rust, you don't need this crate. The sort is as of recently implemented in libcore.

Use it like this:

`#!``[``feature``(``sort_unstable``)``]`
`let` `mut` v `=` `[``-``5``,` `4``,` `1``,` `-``3``,` `2``]``;`
v`.``sort_unstable``(``)``;`
`assert!``(`v `==` `[``-``5``,` `-``3``,` `1``,` `2``,` `4``]``)``;`

See The Unstable Book for more information.

#### Properties

- Best-case running time is

.`O``(`n`)` - Worst-case running time is

.`O``(`n log n`)` - Unstable, i.e. may reorder equal elements.
- Does not allocate additional memory.
- Uses

.`#!``[``no_std``]`

#### Examples

`extern` `crate` pdqsort`;`
`let` `mut` v `=` `[``-``5``i32``,` `4``,` `1``,` `-``3``,` `2``]``;`
`pdqsort``::`sort`(``&``mut` v`)``;`
`assert!``(`v `==` `[``-``5``,` `-``3``,` `1``,` `2``,` `4``]``)``;`
`pdqsort``::`sort_by`(``&``mut` v`,` `|``a``,` `b``|` `b``.``cmp``(`a`)``)``;`
`assert!``(`v `==` `[``4``,` `2``,` `1``,` `-``3``,` `-``5``]``)``;`
`pdqsort``::`sort_by_key`(``&``mut` v`,` `|``k``|` `k``.``abs``(``)``)``;`
`assert!``(`v `==` `[``1``,` `2``,` `-``3``,` `4``,` `-``5``]``)``;`

#### A simple benchmark

Sorting 10 million random numbers of type

:`u64`

Sort | Time |
---|---|

pdqsort | 370 ms |

slice::sort | 668 ms |

quickersort | 777 ms |

rdxsort | 602 ms |