leetcode 448 Find All Numbers Disappeared in an Array

Posted 2021-01-26 ctqchina

class Solution {
    public List<Integer> findDisappearedNumbers(int[] nums) {
        
        int n = nums.length;
        ArrayList<Integer> ans = new ArrayList<Integer>();
       boolean[] vis = new boolean[n+1];
        for(int i=0;i<n;i++){
            vis[nums[i]] = true;
        }
        for(int i=1;i<=n;i++){
            if(!vis[i]) ans.add(i);
        }
        
        
        return ans;
    }
}

　　时间复杂度O(n)，空间复杂度O(n)。空间复杂度O(1)的不会做- -待补