The basic idea ：

Enter a linked list , Output the last number in the list k Nodes . In order to conform to the habits of most people , From 1 Start counting , That is, the tail node of the list is the last 1 Nodes .

for example , A list has 6 Nodes , Start from the beginning , Their values, in turn, are 1、2、3、4、5、6. The last of the list 3 Each node has a value of 4 The node of .

No idea , Just mark it with a pointer ;

Specific code ：

class Solution {
    
public:
    vector<int> exchange(vector<int>& nums) {
    
        int l=0;
        for(int i=0;i<nums.size();i++){
    
            if(nums[i]%2==1){
    
                swap(nums[i], nums[l]);
                l++;
            }
        }
        return nums;
    }
};