//Given a collection of distinct numbers, return all possible permutations.
//
//For example,
//[1,2,3] have the following permutations:
//[
//[1,2,3],
//[1,3,2],
//[2,1,3],
//[2,3,1],
//[3,1,2],
//[3,2,1]
//]
class Permutations {
public List<List<Integer>> permute(int[] nums) {
LinkedList<List<Integer>> result = new LinkedList<List<Integer>>();
result.add(new ArrayList<Integer>());
for (int n: nums) {
int size = result.size();
while(size > 0) {
List<Integer> current = result.pollFirst();
for (int i = 0; i <= current.size(); i++) {
List<Integer> temp = new ArrayList<Integer>(current);
temp.add(i, n);
result.add(temp);
}
size--;
}
}
return result;
}
}
//
//For example,
//[1,2,3] have the following permutations:
//[
//[1,2,3],
//[1,3,2],
//[2,1,3],
//[2,3,1],
//[3,1,2],
//[3,2,1]
//]
class Permutations {
public List<List<Integer>> permute(int[] nums) {
LinkedList<List<Integer>> result = new LinkedList<List<Integer>>();
result.add(new ArrayList<Integer>());
for (int n: nums) {
int size = result.size();
while(size > 0) {
List<Integer> current = result.pollFirst();
for (int i = 0; i <= current.size(); i++) {
List<Integer> temp = new ArrayList<Integer>(current);
temp.add(i, n);
result.add(temp);
}
size--;
}
}
return result;
}
}
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