lostecho/grokking_algorithms
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

add examples in java 8 (#12)

Browse Source 
* code for chapters 3-9 in Java

* code for chapters 1 in Java

* code for chapter 2 in Java

* missing CheckVoter for chapter 5 in Java

* add missing sample output for SetCovering as a comment
This commit is contained in:
Oleh Novikov
2017-03-20 17:06:45 +01:00
committed by Aditya Bhargava
parent 12265a8c61
commit 4631b7a156
17 changed files with 502 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

37
08_greedy_algorithms/java/01_set_covering/src/SetCovering.java Normal file
View File

@@ -0,0 +1,37 @@
import java.util.*;
public class SetCovering {
public static void main(String[] args) {
Set<String> statesNeeded = new HashSet(Arrays.asList("mt", "wa", "or", "id", "nv", "ut", "ca", "az"));
Map<String, Set<String>> stations = new LinkedHashMap<>();
stations.put("kone", new HashSet<>(Arrays.asList("id", "nv", "ut")));
stations.put("ktwo", new HashSet<>(Arrays.asList("wa", "id", "mt")));
stations.put("kthree", new HashSet<>(Arrays.asList("or", "nv", "ca")));
stations.put("kfour", new HashSet<>(Arrays.asList("nv", "ut")));
stations.put("kfive", new HashSet<>(Arrays.asList("ca", "az")));
Set<String> finalStations = new HashSet<String>();
while (!statesNeeded.isEmpty()) {
String bestStation = null;
Set<String> statesCovered = new HashSet<>();
for (Map.Entry<String, Set<String>> station : stations.entrySet()) {
Set<String> covered = new HashSet<>(statesNeeded);
covered.retainAll(station.getValue());
if (covered.size() > statesCovered.size()) {
bestStation = station.getKey();
statesCovered = covered;
}
statesNeeded.removeIf(statesCovered::contains);
if (bestStation != null) {
finalStations.add(bestStation);
}
}
}
System.out.println(finalStations); // [ktwo, kone, kthree, kfive]
}
}