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java:jfc_algorithms [2015/03/17 14:34] gthanos |
java:jfc_algorithms [2016/02/26 11:15] |
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| - | ====== Αλγόριθμοι ====== | ||
| - | Οι βασικοί αλγόριθμοι του JFC υλοποιούνται στην κλάση [[http://docs.oracle.com/javase/7/docs/api/java/util/Collections.html|Collections]]. | ||
| - | |||
| - | * **sorting:** [[java:jfc_intf_sort|(δείτε τα παραδείγματα)]]. (N Log(n) performance). | ||
| - | <code java Sort.java> | ||
| - | import java.util.*; | ||
| - | |||
| - | public class Sort { | ||
| - | public static void main(String[] args) { | ||
| - | List<String> list = Arrays.asList(args); | ||
| - | Collections.sort(list); | ||
| - | System.out.println(list); | ||
| - | } | ||
| - | } | ||
| - | </code> | ||
| - | |||
| - | * **shuffling (ανακάτεμα):** shuffle(List<?> list) ή shuffle(List<?> list, Random rnd). | ||
| - | <code java Shuffle.java> | ||
| - | import java.util.*; | ||
| - | |||
| - | public class Shuffle { | ||
| - | public static void main(String[] args) { | ||
| - | List<String> list = Arrays.asList(args); | ||
| - | Collections.shuffle(list); | ||
| - | System.out.println(list); | ||
| - | } | ||
| - | } | ||
| - | </code> | ||
| - | * **reverse:** | ||
| - | <code java Reverse.java> | ||
| - | import java.util.*; | ||
| - | |||
| - | public class Reverse { | ||
| - | public static void main(String[] args) { | ||
| - | List<String> list = Arrays.asList(args); | ||
| - | Collections.reverse(list); | ||
| - | System.out.println(list); | ||
| - | } | ||
| - | } | ||
| - | </code> | ||
| - | * **fill:** | ||
| - | <code java Fill.java> | ||
| - | import java.util.*; | ||
| - | |||
| - | public class Fill { | ||
| - | public static void main(String[] args) { | ||
| - | List<String> list = Arrays.asList(args); | ||
| - | System.out.println("List elements before fill: "+list); | ||
| - | Collections.fill(list,"HelloWorld!"); | ||
| - | System.out.println("List elements after fill: "+list); | ||
| - | } | ||
| - | } | ||
| - | </code> | ||
| - | * **copy:** | ||
| - | <code java Copy.java> | ||
| - | |||
| - | import java.util.*; | ||
| - | |||
| - | public class Copy { | ||
| - | public static void main(String args[]) { | ||
| - | // create two lists | ||
| - | List<String> srclst = new ArrayList<String>(5); | ||
| - | List<String> destlst = new ArrayList<String>(10); | ||
| - | | ||
| - | // populate two lists | ||
| - | srclst.add("Java"); | ||
| - | srclst.add("is"); | ||
| - | srclst.add("best"); | ||
| - | | ||
| - | destlst.add("C++"); | ||
| - | destlst.add("is"); | ||
| - | destlst.add("older"); | ||
| - | destlst.add("and"); | ||
| - | destlst.add("fast!"); | ||
| - | | ||
| - | // copy into dest list | ||
| - | Collections.copy(destlst, srclst); | ||
| - | | ||
| - | System.out.println("Value of source list: "+srclst); | ||
| - | System.out.println("Value of destination list: "+destlst); | ||
| - | } | ||
| - | </code> | ||
| - | * **swap:** | ||
| - | <code java Swap.java> | ||
| - | import java.util.*; | ||
| - | |||
| - | public class Swap { | ||
| - | public static void main(String[] args) { | ||
| - | List<String> list = Arrays.asList(args); | ||
| - | System.out.println("List elements before swap: "+list); | ||
| - | Collections.swap(list); | ||
| - | System.out.println("List elements after swap: "+list); | ||
| - | } | ||
| - | } | ||
| - | </code> | ||
| - | * **addAll:** | ||
| - | * **frequency:** | ||
| - | <code java Frequency.java> | ||
| - | import java.util.*; | ||
| - | |||
| - | public class Frequency { | ||
| - | public static void main(String[] args) { | ||
| - | List<String> list = Arrays.asList(args); | ||
| - | int testFreq = Collections.frequency(list, "test"); | ||
| - | System.out.println("\"test\" appears "+testFreq+" times"); | ||
| - | } | ||
| - | } | ||
| - | </code> | ||
| - | |||
| - | * **min:** | ||
| - | * **max:** | ||
| - | <code java MinMax.java> | ||
| - | import java.util.*; | ||
| - | |||
| - | public class MinMax { | ||
| - | public static void main(String[] args) { | ||
| - | List<String> list = Arrays.asList(args); | ||
| - | | ||
| - | System.out.println("Min value: "+Collections.min(list,null)+" | Max value: "+Collections.max(list,null) ); | ||
| - | } | ||
| - | } | ||
| - | </code> | ||