User:Margusmartsepp/Contributions/Java/Utils.java: Difference between revisions
(Created page with "<lang java> import java.util.ArrayList; import java.util.Collections; public class Utils<T extends Comparable<T>> { private void swap(ArrayList<T> data, int i, int j) { T t =...") |
No edit summary |
||
| Line 3: | Line 3: | ||
import java.util.Collections; |
import java.util.Collections; |
||
public class Utils |
public class Utils { |
||
private void swap(ArrayList<T> data, int i, int j) { |
private static <T> void swap(ArrayList<T> data, int i, int j) { |
||
T t = data.get(i); |
T t = data.get(i); |
||
data.set(i, data.get(j)); |
data.set(i, data.get(j)); |
||
| Line 10: | Line 10: | ||
} |
} |
||
public ArrayList<Integer> mRange(int from, int to) { |
public static ArrayList<Integer> mRange(int from, int to) { |
||
ArrayList<Integer> result = new ArrayList<Integer>(); |
ArrayList<Integer> result = new ArrayList<Integer>(); |
||
for (int i = from; i <= to; i++) |
for (int i = from; i <= to; i++) |
||
| Line 17: | Line 17: | ||
} |
} |
||
public boolean nextPerm(ArrayList<T> data) { |
public static <T extends Comparable<? super T>> boolean nextPerm(ArrayList<T> data) { |
||
// find the swaps |
// find the swaps |
||
int c = -1, d = data.size(); |
int c = -1, d = data.size(); |
||
| Line 43: | Line 43: | ||
} |
} |
||
| ⚫ | |||
@SuppressWarnings("unchecked") |
|||
| ⚫ | |||
ArrayList<ArrayList<T>> result = new ArrayList<ArrayList<T>>(); |
ArrayList<ArrayList<T>> result = new ArrayList<ArrayList<T>>(); |
||
Collections.sort(d); |
Collections.sort(d); |
||
do { |
do { |
||
result.add( |
result.add(new ArrayList<T>(d)); |
||
} while ( |
} while (nextPerm(d)); |
||
return result; |
return result; |
||
} |
} |
||
Revision as of 05:17, 28 October 2010
<lang java> import java.util.ArrayList; import java.util.Collections;
public class Utils { private static <T> void swap(ArrayList<T> data, int i, int j) { T t = data.get(i); data.set(i, data.get(j)); data.set(j, t); }
public static ArrayList<Integer> mRange(int from, int to) { ArrayList<Integer> result = new ArrayList<Integer>(); for (int i = from; i <= to; i++) result.add(i); return result; }
public static <T extends Comparable<? super T>> boolean nextPerm(ArrayList<T> data) { // find the swaps int c = -1, d = data.size(); for (int i = d - 2; i >= 0; i--) if (data.get(i).compareTo(data.get(i + 1)) < 0) { c = i; break; }
if (c < 0) return false;
int s = c + 1; for (int j = c + 2; j < d; j++) if (data.get(j).compareTo(data.get(s)) < 0 && // data.get(j).compareTo(data.get(c)) > 0) s = j;
// do the swaps swap(data, c, s); while (--d > ++c) swap(data, c, d);
return true; }
public static <T extends Comparable<? super T>> ArrayList<ArrayList<T>> Permutations(ArrayList<T> d) { ArrayList<ArrayList<T>> result = new ArrayList<ArrayList<T>>(); Collections.sort(d); do { result.add(new ArrayList<T>(d)); } while (nextPerm(d)); return result; } } </lang>