Leetcode 448 找到所有数组中消失的数字

Posted 2023-03-05 Z-Pilgrim

https://leetcode.cn/problems/find-all-numbers-disappeared-in-an-array/

模拟一下还是比较容易能找到解法  但是官方答案更骚

class Solution 
public:
    vector<int> findDisappearedNumbers(vector<int>& nums) 
        for(int i = 0; i < nums.size(); ) 
            if(nums[i] == i+1) 
                i++; 
             else 
                int new_idx = nums[i] - 1;
                if(nums[new_idx] == new_idx + 1) 
                    i++;
                 else 
                    swap(nums[i], nums[new_idx]);
                
            
        
        vector<int> ans;
        for(int i = 0; i < nums.size(); i++) 
            if(nums[i] != i+1) 
                ans.push_back(i+1);
            
        
        return ans;
    
;

官方：https://leetcode.cn/problems/find-all-numbers-disappeared-in-an-array/solution/zhao-dao-suo-you-shu-zu-zhong-xiao-shi-d-mabl/

等于是利用值域没有用完 做了一个原地hash

        int n = nums.size();
        for (auto& num : nums) 
            int x = (num - 1) % n;
            nums[x] += n;
        
        vector<int> ret;
        for (int i = 0; i < n; i++) 
            if (nums[i] <= n) 
                ret.push_back(i + 1);
            
        
        return ret;
    

作者：LeetCode-Solution
链接：https://leetcode.cn/problems/find-all-numbers-disappeared-in-an-array/solution/zhao-dao-suo-you-shu-zu-zhong-xiao-shi-d-mabl/
来源：力扣（LeetCode）
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