Permutation
Backtracking
My Code
LeetCode
46. Permutations
- 使用 遞迴
- 使用 trackBacking (因為要找出所有可能，使用回溯法)
- 元素皆出現一次
Given an array nums of distinct integers, return all the possible permutations. You can return the answer in any order.
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| class Solution {
public List<List<Integer>> permute(int[] nums) {
List<List<Integer>> resultList = new ArrayList<>();
backtracking(resultList, new ArrayList<>(), nums);
return resultList;
}
private void backtracking(List<List<Integer>> resultList, ArrayList tempList, int[] nums) {
if (tempList.size() == nums.length){
resultList.add(new ArrayList<>(tempList));
return;
}
for (int num : nums) {
if (tempList.contains(num)) {
continue;
}
tempList.add(num);
backtracking(resultList, tempList, nums);
tempList.remove(tempList.size() - 1);
}
}
}
|