每个槽位可以选什么数字, dfs, 记录哪个数字用过了
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| class Solution {
public List<List<Integer>> permute(int[] nums) {
int n = nums.length;
List<List<Integer>> ans = new ArrayList<>();
List<Integer> permutation = Arrays.asList(new Integer[n]);;
dfs(0, nums, permutation, new boolean[n], ans);
return ans;
}
private void dfs(int i, int[] nums, List<Integer> permutation, boolean[] visited, List<List<Integer>> ans) {
if (i == nums.length) {
ans.add(new ArrayList<>(permutation));
return ;
}
for (int j = 0; j < nums.length; j++) {
if (visited[j])
continue;
permutation.set(i, nums[j]);
visited[j] = true;
dfs(i+1, nums, permutation, visited, ans);
visited[j] = false;
}
}
}
|
